| Genus |
Order |
Reference |
Note |
Nomenclature |
| P | |
| Pabia | Prasiolales | Darienko et al. (2010) | As Prasiola-clade. | ICBN |
| Pabstia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pachastrella | Astrophorida | Maldonado (2002) | . | ICZN |
| Pachastrissa | Astrophorida | Van Soest & Hooper (2002) | . | ICZN |
| Pachataxa | Astrophorida | Van Soest & Hooper (2002) | . | ICZN |
| Pachira | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pachites | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pachyanthus | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pachyarthron | Corallinales | Schneider & Wynne (2007) | . | ICBN |
| Pachycalamus | Squamata | Vitt & Caldwell (2009) | Trogonophidae. | ICZN |
| Pachycare | Passeriformes | Clements (2007) | . | ICZN |
| Pachycarpus | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pachycentria | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pachycephala | Passeriformes | Clements (2007) | . | ICZN |
| Pachycephalopsis | Passeriformes | Clements (2007) | . | ICZN |
| Pachycereus | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pachycerianthus | Ceriantharia | Tiffon (1987) | . | ICZN |
| Pachychaeta | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pachychalina | Haplosclerida | Desqueyroux-Faúndez & Valentine (2002) | . | ICZN |
| Pachycladon | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pachyclavularia | Alcyonacea | Bayer (1981) | Tubiporidae. | ICZN |
| Pachycoccyx | Cuculiformes | Clements (2007) | . | ICZN |
| Pachycordyne | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pachycormus | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pachycornia | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pachycrocuta | Carnivora | McKenna & Bell (1997); Wozencraft (2005) | Later synonym of Hyaena. | ICZN |
| Pachyctenium | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pachydactylus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Pachydictyum | Haplosclerida | Manconi & Pronzato (2002) | . | ICZN |
| Pachydinium | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Pachyelasma | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pachyfolliculina | Heterotrichida | Lynn (2008) | . | ICZN |
| Pachyglossa | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pachygone | Ranunculales | Mabberley (2008) | Menispermaceae. | ICBN |
| Pachyhynobius | Caudata | Vitt & Caldwell (2009) | Hynobiidae. | ICZN |
| Pachyjoenia | Cristamonadida | Cepicka et al. (2010) | . | ICZN |
| Pachylaena | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pachyloma | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pachymatisma | Astrophorida | Uriz (2002) | . | ICZN |
| Pachymedusa | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Pachymenia | Cryptonemiales | Silva (2002); Schneider & Wynne (2007) | . | ICBN |
| Pachymeniopsis | Cryptonemiales | Silva (2002); Schneider & Wynne (2007) | Later synonym of Grateloupia. | ICBN |
| Pachymetra | Saprolegniales | Riethmüller et al. (1999); Dick (2001); Kirk et al. (2008) | Leptolegniaceae. | ICBN |
| Pachymitus | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pachynema | Dilleniales | Mabberley (2008) | Dilleniaceae. | ICBN |
| Pachynemertes | Pelagica | Gibson (1995) | . | ICZN |
| Pachyneuropsis | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Pachyneurum | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pachypellina | Haplosclerida | Desqueyroux-Faúndez & Valentine (2002) | . | ICZN |
| Pachyphantes | Passeriformes | Clements (2007) | . | ICZN |
| Pachyphragma | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pachyphyllum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pachyphytum | Saxifragales | Mabberley (2008) | Crassulaceae. | ICBN |
| Pachyplectron | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pachypleurum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pachypodium | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pachyporospora | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pachyptera | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Pachypterygium | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pachyptila | Procellariiformes | Clements (2007) | . | ICZN |
| Pachyramphus | Passeriformes | Clements (2007) | . | ICZN |
| Pachyrhizus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pachyrotula | Haplosclerida | Manconi & Pronzato (2002) | . | ICZN |
| Pachysandra | Buxales | Mabberley (2008) | Buxaceae. | ICBN |
| Pachyschistochila | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pachysentis | Oligacanthorhynchida | Amin (1985) | . | ICZN |
| Pachyseris | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Pachysoeca | Craspedida | Leadbeater & Thomsen (2000) | . | ICZN |
| Pachystachys | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pachystigma | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pachystoma | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pachystomos | | Lynn (2008) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora. | ICZN |
| Pachystroma | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pachystylidium | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pachystylus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pachytriton | Caudata | Vitt & Caldwell (2009) | Salamandridae. | ICZN |
| Pachytrocha | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Pachyuromys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pachyveria | Saxifragales | Mabberley (2008) | xPachyveria. Echeveria x Pachyphytum hybrids. Crassulaceae. | ICBN |
| Pacificibacter | Rhodobacterales | Romanenko et al. (2011) | . | ICNB |
| Pacifigeron | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pacifigorgia | Alcyonacea | Bayer (1981) | Gorgoniidae. | ICZN |
| Pacinonion | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nonionidae. | ICZN |
| Packera | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pacouria | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pacourina | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Padda | Passeriformes | Clements (2007) | . | ICZN |
| Paederia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paedomecynostomum | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Paenalcaligenes | Burkholderiales | Kämpfer et al. (2010) | . | ICNB |
| Paenibacillus | Bacillales | Garrity et al. (2005) | . | ICNB |
| Paenisporosarcina | Bacillales | Krishnamurthi et al. (2009) | . | ICNB |
| Paenochrobactrum | Rhizobiales | Kämpfer et al. (2010) | . | ICNB |
| Paeonia | Saxifragales | Mabberley (2008) | Paeoniaceae. | ICBN |
| Paepalanthus | Poales | Mabberley (2008) | Eriocaulaceae. | ICBN |
| Paesia | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pagamea | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pagameopsis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pagodroma | Procellariiformes | Clements (2007) | . | ICZN |
| Pagophila | Charadriiformes | Clements (2007) | . | ICZN |
| Pagophilus | Carnivora | Wozencraft (2005) | . | ICZN |
| Paguma | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Painteria | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pajanelia | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Pakaraimaea | Malvales | Mabberley (2008) | Dipterocarpaceae. | ICBN |
| Palaeococcus | Thermococcales | Garrity et al. (2005) | . | ICNB |
| Palafoxia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Palamocladium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Palaquium | Ericales | Mabberley (2008) | Sapotaceae. | ICBN |
| Palatinus | | Craveiro et al. (2009) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Dinozoa - Class Dinophyceae. | ICBN |
| Palaua | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Palauastrea | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Palavascia | Ichthyophonida | Cafaro (2005); Kirk et al. (2008) | Eccrinales in mycology. | ICZN |
| Palawanomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Palea | Testudinata | Vitt & Caldwell (2009) | Trionychidae. | ICZN |
| Paleodicraeia | Malpighiales | Mabberley (2008) | Podostemaceae. | ICBN |
| Paleophalacroma | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Paleosuchus | Crocodylia | Vitt & Caldwell (2009) | Alligatoridae. | ICZN |
| Paleozoanthus | Zoanthidea | Sinniger et al. (2005) | . | ICZN |
| Palephyra | Coronatae | Kramp (1961) | . | ICZN |
| Palicourea | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Palikiella | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Palimbia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Palisada | Ceramiales | Wynne & Schneider (2010) | . | ICBN |
| Palisadula | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Palisota | Commelinales | Mabberley (2008) | Commelinaceae. | ICBN |
| Paliurus | Rosales | Mabberley (2008) | Rhamnaceae. | ICBN |
| Pallavicinia | Fossombroniales | He-Nygrén et al. (2006); Crandall-Stotler et al. (2009) | . | ICBN |
| Pallenis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Palleronia | Rhodobacterales | Martínez-Checa et al. (2005) | . | ICNB |
| Palliatus | Bivalvulida | Lom & Dyková (2006) | . | ICZN |
| Palliolatella | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ellipsolagenidae. | ICZN |
| Palliolisentis | Gyracanthocephala | Amin (1985) | . | ICZN |
| Pallisentis | Gyracanthocephala | Amin (1985) | . | ICZN |
| Pallitrichodina | Mobilida | Lynn (2008) | . | ICZN |
| Palmarella | Armophorida | Lynn (2008) | . | ICZN |
| Palmaria | Palmariales | Schneider & Wynne (2007) | . | ICBN |
| Palmatogecko | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Palmatorappia | Anura | Vitt & Caldwell (2009) | Ceratobatrachidae. | ICZN |
| Palmerella | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Palmeria | Passeriformes | Clements (2007) | . | ICZN |
| Palmeria | Laurales | Mabberley (2008) | Monimiaceae. | ICBN |
| Palmerinella | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Epistomariidae. | ICZN |
| Palmoclathrus | | Zechman et al. (2010) | Domain Eucarya - Kingdom Plantae - Subkingdom Viridiplantae. Possibly related to Palmophyllales. | ICBN |
| Palmophyllum | Palmophyllales | Zechman et al. (2010) | . | ICBN |
| Palmorchis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Paloue | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Paloveopsis | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Palpitomonas | | Yabuki et al. (2010) | Domain Eucarya (probably a member of bikonts). | ICZN |
| Paludella | Splachnales | Goffinet et al. (2009) | . | ICBN |
| Paludibacter | Bacteroidales | Ueki et al. (2006) | . | ICNB |
| Paludibacterium | Neisseriales | Kwon et al. (2008) | . | ICNB |
| Paludipasser | Passeriformes | Clements (2007) | . | ICZN |
| Palumbina | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Palusphaera | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | Rhabdosphaeraceae. | ICBN |
| Palustrella | Lituolida | Kaminski (2000) | Palustrellinae, Verneuilinacea. | ICZN |
| Palustriella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Palythoa | Zoanthidea | Sinniger et al. (2005) | . | ICZN |
| Pamburus | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pamelaescincus | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Pamianthe | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Pan | Primates | McKenna & Bell (1997) | . | ICZN |
| Panacagrimonas | Xanthomonadales | Im et al. (2010) | . | ICNB |
| Panamanthus | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Panaspis | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Panax | Apiales | Mabberley (2008) | Araliaceae. | ICBN |
| Pancheria | Oxalidales | Mabberley (2008) | Cunoniaceae. | ICBN |
| Pancicia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pancovia | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Pancratium | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Panda | Malpighiales | Mabberley (2008) | Pandaceae. | ICBN |
| Pandaglandulina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nodosariidae. | ICZN |
| Pandanus | Pandanales | Mabberley (2008) | Pandanaceae. | ICBN |
| Pandaros | Poecilosclerida | Hooper (2002) | . | ICZN |
| Pandea | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pandeopsis | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Panderia | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pandiaka | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pandion | Falconiformes | Clements (2007) | . | ICZN |
| Pandoraea | Burkholderiales | Garrity et al. (2005) | . | ICNB |
| Pandorea | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Pandosentis | Neoechinorhynchida | Amin (1985) | . | ICZN |
| Pangium | Malpighiales | Mabberley (2008) | Achariaceae. | ICBN |
| Panicum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Panisea | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pankovaia | Microsporida | Simakova et al. (2009) | . | ICZN |
| Pannellaina | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pannellainidae. | ICZN |
| Pannonibacter | Rhodobacterales | Garrity et al. (2005) | . | ICNB |
| Pannus | Synechococcales | Hoffmann et al. (2005) | . | ICBN |
| Panopsis | Proteales | Mabberley (2008) | Proteaceae. | ICBN |
| Panorhynchus | Heteronemertea | Gibson (1995) | . | ICZN |
| Panphalea | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pantacantha | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Pantachogon | Trachymedusae | Bouillon et al. (2006) | . | ICZN |
| Pantachordodes | Gordioidea | Schmidt-Rhaesa (2002); Poinar Jr. (2008) | . | ICZN |
| Pantadenia | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Panterpe | Apodiformes | Clements (2007) | . | ICZN |
| Panthera | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Pantherophis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pantholops | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Artiodactyla. | ICZN |
| Pantinonemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Pantlingia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pantoea | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Pantoneura | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Panurea | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Panurus | Passeriformes | Clements (2007) | . | ICZN |
| Panyptila | Apodiformes | Clements (2007) | . | ICZN |
| Panzerina | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Papagomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Papaver | Ranunculales | Mabberley (2008) | Papaveraceae. | ICBN |
| Papenfussia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Paphia | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Paphinia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Paphiopedilum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Papilionanthe | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Papilionella | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Papillibacter | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Papillidiopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Papillilabium | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Papillorhabdos | Haptorida | Lynn (2008) | . | ICZN |
| Papio | Primates | McKenna & Bell (1997) | . | ICZN |
| Papistylus | Rosales | Mabberley (2008) | Rhamnaceae. | ICBN |
| Pappea | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Papperitzia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pappobolus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pappogeomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pappomonas | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | Papposphaeraceae. | ICBN |
| Pappophorum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Papposphaera | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | Papposphaeraceae. | ICBN |
| Papuacalia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Papuacedrus | Cupressales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Papuaea | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Papuanthes | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Papuascincus | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Papuasicyos | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Papuechites | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Parabacteroides | Bacteroidales | Sakamoto & Benno (2006) | . | ICNB |
| Parabaena | Ranunculales | Mabberley (2008) | Menispermaceae. | ICBN |
| Parabalaenanemertes | Pelagica | Gibson (1995) | . | ICZN |
| Parabambusa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Parabirojimia | Urostylida | Lynn (2008) | . | ICZN |
| Parablaste | | Lynn (2008) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora. | ICZN |
| Parablepharisma | Heterotrichida | Lynn (2008) | . | ICZN |
| Parabodo | Parabodonida | Moreira et al. (2004) | . | ICZN |
| Paraboea | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Parabrizalina | Buliminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Siphogenerinoididae. | ICZN |
| Parabryophrya | Colpodida | Lynn (2008); Bourland et al. (2011) | . | ICZN |
| Parabundleia | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Parabunodactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Parabuteo | Falconiformes | Clements (2007) | . | ICZN |
| Paracaleana | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Paracalia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Paracalliactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paracalyptrophora | Alcyonacea | Bayer (1981) | Primnoidae. | ICZN |
| Paracalyx | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Paracanthocephaloides | Echinorhynchida | Amin (1985) | . | ICZN |
| Paracanthorhynchus | Echinorhynchida | Amin (1985) | . | ICZN |
| Paracapsa | Synechococcales | Hoffmann et al. (2005) | . | ICBN |
| Paracaryopsis | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Paracaryum | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Paracassidulina | Buliminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Cassidulinidae. | ICZN |
| Paracassina | Anura | Vitt & Caldwell (2009) | Hyperoliidae. | ICZN |
| Paracavisoma | Echinorhynchida | Amin (1985) | . | ICZN |
| Paracentrophyes | Homalorhagida | Higgins (1990) | . | ICZN |
| Paracentropyxis | Arcellinida | Meisterfeld (2000) | Difflugina -- Plagiopyxidae. | ICZN |
| Paracephaelis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paracercomonas | Cercomonadida | Karpov et al. (2006); Howe et al. (2009) | . | ICZN |
| Paracerebratulus | Heteronemertea | Kajihara et al. (2008) | . | ICZN |
| Paraceterach | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Parachaos | Euamoebida | Rogerson & Patterson (2000); Smirnov et al. (2005) | . | ICZN |
| Parachilodonella | Dysteriida | Lynn (2008) | . | ICZN |
| Parachimarrhis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Parachlamydia | Chlamydiales | Garrity et al. (2005) | . | ICNB |
| Parachlorella | Chlorellales | Krienitz et al. (2010) | Parachlorella clade in Chlorellaceae. | ICBN |
| Parachoanocystoides | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Parachordodes | Gordioidea | Schmidt-Rhaesa (2002); Poinar Jr. (2008) | . | ICZN |
| Paracibicides | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Cibicididae. | ICZN |
| Paracichlidotherus | Clevelandellida | Lynn (2008) | . | ICZN |
| Paracineta | Exogenida | Lynn (2008) | . | ICZN |
| Paracis | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Paraclathrostoma | Peniculida | Lynn (2008) | . | ICZN |
| Paraclausilocola | Astomatida | Fokam et al. (2011) | . | ICZN |
| Paraclavarina | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Paraclevelandia | Clevelandellida | Lynn (2008) | . | ICZN |
| Paracoccus | Rhodobacterales | Garrity et al. (2005) | . | ICNB |
| Paracoelophrya | Astomatida | Lynn (2008) | . | ICZN |
| Paracoelops | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Paracollinia | Apostomatida | Lynn (2008) | . | ICZN |
| Paracolpidium | Tetrahymenida | Lynn (2008) | . | ICZN |
| Paracolurella | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Paracondylactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paracondylostoma | Bursariomorphida | Lynn (2008) | . | ICZN |
| Paraconotrochus | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Paracontias | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Paracorallium | Alcyonacea | Bayer & Cairns (2003) | Coralliidae. | ICZN |
| Paracornulum | Poecilosclerida | Hooper (2002) | . | ICZN |
| Paracorynanthe | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paracoryne | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Paracostus | Zingiberales | Mabberley (2008) | Costaceae. | ICBN |
| Paracraurococcus | Rhodospirillales | Garrity et al. (2005) | . | ICNB |
| Paracrinia | Anura | Vitt & Caldwell (2009) | Myobatrachidae. | ICZN |
| Paracrocidura | Eulipotyphla | McKenna & Bell (1997); Murphy et al. (2001) | . | ICZN |
| Paracromastigum | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Paracroton | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Paracryphia | Paracryphiales | Mabberley (2008) | Paracryphiaceae. | ICBN |
| Paractaenum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Paractedectema | Pleuronematida | Lynn (2008) | . | ICZN |
| Paractedoctema | Pleuronematida | Lynn (2008) | . | ICZN |
| Paractinia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paractinoposthia | Acoela | Hooge (2001) | Under confirmation. | ICZN |
| Paractinostola | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paractis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paraculeolus | Stolidobranchia | Monniot & Monniot (1972) | Pyuridae. | ICZN |
| Paracunhamunizia | Vestibuliferida | Lynn (2008) | . | ICZN |
| Paracyathus | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Paracyclidium | Pleuronematida | Lynn (2008) | . | ICZN |
| Paracycloposthium | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Paracynictis | Carnivora | Wozencraft (2005) | . | ICZN |
| Paracyrtophoron | Chlamydodontida | Chen et al. (2012) | . | ICZN |
| Paracytaeis | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Paradactylactis | Ceriantharia | Tiffon (1987) | . | ICZN |
| Paradactylodon | Caudata | Vitt & Caldwell (2009) | Hynobiidae. | ICZN |
| Paradasys | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Paradelma | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Paradermamoeba | Dermamoebida | Rogerson & Patterson (2000); Cavalier-Smith et al. (2004); Smirnov et al. (2011) | . | ICZN |
| Paraderris | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Paradesmanthus | | Pisera & Lévi (2002) | Domain Eucarya - Kingdom Animalia - Phylum Porifera - Class Demospongiae (lithistids) Desmanthidae. | ICZN |
| Paradexiotricha | Philasterida | Lynn (2008) | . | ICZN |
| Paradiachea | Stemonitales | Yamamoto (1998) | . | ICBN |
| Paradiacheopsis | Stemonitales | Yamamoto (1998) | . | ICBN |
| Paradicranophorus | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Paradileptus | Haptorida | Lynn (2008) | . | ICZN |
| Paradinium | Paradinida | Bass et al. (2009) | . | ICZN |
| Paradinonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Paradiophrys | Euplotida | Lynn (2008) | . | ICZN |
| Paradiphascon | Parachela | Kinchin (1994) | . | ICZN |
| Paradipus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Paradisaea | Passeriformes | Clements (2007) | . | ICZN |
| Paradisanthus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Paradiscocephalus | Euplotida | Li et al. (2008) | . | ICZN |
| Paradisea | Asparagales | Mabberley (2008) | Asparagaceae. | ICBN |
| Paradogalla | Passeriformes | Clements (2007) | . | ICZN |
| Paradoliopsis | Doliolida | Godeaux & Harbison (2003) | . | ICZN |
| Paradombeya | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Paradoxia | | Letsch et al. (2009); Darienko et al. (2010) | Domain Eucarya - Phylum Chlorophyta - Class Trebouxiophyceae. Elliptochloris-clade. | ICBN |
| Paradoxipus | Arthrotardigrada | Kinchin (1994) | . | ICZN |
| Paradoxophyla | Anura | Vitt & Caldwell (2009) | Microhylidae. | ICZN |
| Paradoxornis | Passeriformes | Clements (2007) | . | ICZN |
| Paradoxurus | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Paradrepanophorus | Reptantia | Gibson (1995) | . | ICZN |
| Paradrymonia | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Paradrypetes | Malpighiales | Mabberley (2008) | Rhizophoraceae. | ICBN |
| Paraechinus | Erinaceomorpha | Hutterer (2005) | . | ICZN |
| Paraedwardsia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paraeggerthella | Coriobacteriales | Würdemann et al. (2009); Ludwig et al. (2012) | . | ICNB |
| Paraenchelys | Haptorida | Lynn (2008) | . | ICZN |
| Paraerrina | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Paraeukrohnia | Phragmophora | Kasatkina & Stolyarova (2006) | Eukrohniidae. | ICZN |
| Paraeuplotes | Euplotida | Lynn (2008) | . | ICZN |
| Parafaujasia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Parafavella | Tintinnida | Lynn (2008) | . | ICZN |
| Parafavelloides | Tintinnida | Lynn (2008) | . | ICZN |
| Paraferrimonas | Alteromonadales | Khan & Harayama (2007) | . | ICNB |
| Parafissurina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ellipsolagenidae. | ICZN |
| Paraflabellula | Leptomyxida | Rogerson & Patterson (2000); Smirnov et al. (2005) | . | ICZN |
| Parafolliculina | Heterotrichida | Lynn (2008) | . | ICZN |
| Parafrondicularia | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nodosariidae. | ICZN |
| Parafurgasonia | Nassulida | Lynn (2008) | . | ICZN |
| Paragaleus | Carcharhiniformes | Nelson (2006) | . | ICZN |
| Paragalma | Siphonophorae | Bouillon et al. (2006) | . | ICZN |
| Paragastrostyla | Urostylida | Lynn (2008) | . | ICZN |
| Paragatronauta | Chlamydodontida | Lynn (2008) | . | ICZN |
| Paragehyra | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Paragenipa | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Parageum | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Paraglaucoma | Tetrahymenida | Lynn (2008) | . | ICZN |
| Paraglossum | Ceramiales | Schneider & Wynne (2007) | Later synonym of Delesseria. | ICBN |
| Paragnathiella | Bursovaginoidea | Sørensen (2002) | . | ICZN |
| Paragocevia | Himatismenida | Rogerson & Patterson (2000); Cavalier-Smith et al. (2004) | . | ICZN |
| Paragonia | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Paragonospora | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Paragonostomum | Sporadotrichida | Lynn (2008) | . | ICZN |
| Paragordionus | Gordioidea | Schmidt-Rhaesa (2002); Poinar Jr. (2008) | . | ICZN |
| Paragordius | Gordioidea | Schmidt-Rhaesa (2002); Poinar Jr. (2008) | . | ICZN |
| Paragorgia | Alcyonacea | Bayer (1981) | Paragorgiidae. | ICZN |
| Paragorgorhynchus | Echinorhynchida | Amin (1985) | . | ICZN |
| Paragotoea | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Paragramma | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Paragymnodinium | Gymnodiniales | Kang et al. (2010) | . | ICBN |
| Paragymnopteris | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Paragynoxys | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Parahaemoproteus | Haemospororida | Perkins et al. (2000); Martinsen et al. (2008) | . | ICZN |
| Parahalcampa | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Parahancornia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Parahaplogonaria | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Parahaploposthia | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Paraharveya | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Parahauerina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Parahauerinoides | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Parahelicops | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Paraheteropia | Leucosolenida | Borojevic et al. (2002) | . | ICZN |
| Parahigginsia | Halichondrida | Hooper (2002) | . | ICZN |
| Parahistomonas | Tritrichomonadida | Cepicka et al. (2010) | . | ICZN |
| Parahistriculus | Sporadotrichida | Lynn (2008) | Later synonym of Histriculus?. | ICZN |
| Paraholosticha | Stichotrichida | Lynn (2008) | . | ICZN |
| Parahubrechtia | Palaeonemertea | Kajihara et al. (2008) | . | ICZN |
| Parahydromys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Parahydrophis | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Parahyparrhenia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Parahypocoma | Hypocomatida | Lynn (2008) | . | ICZN |
| Paraia | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Paraiptasia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paraisanthus | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paraisometridium | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paraisometrum | Lamiales | Mabberley (2008); Möller et al. (2011) | Gesneriaceae. Later synonym of Oreocharis. | ICBN |
| Paraisotricha | Vestibuliferida | Lynn (2008) | . | ICZN |
| Paraisotrichopsis | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Parajoenia | Cristamonadida | Brugerolle & Lee (2000) | Devescovinidae. | ICZN |
| Parajubaea | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Parakaempferia | Zingiberales | Mabberley (2008) | Zingiberaceae. | ICBN |
| Parakahliella | Stichotrichida | Lynn (2008) | . | ICZN |
| Parakeronopsis | Stichotrichida | Lynn (2008) | nomen nudum. | ICZN |
| Parakibara | Laurales | Mabberley (2008) | Monimiaceae. | ICBN |
| Paraknoxia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paralactobacillus | Lactobacillales | Garrity et al. (2005); Haakensen et al. (2011) | Later synonym of Lactobacillus. | ICNB |
| Paralagenophrys | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Paralamium | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Paralcaligenes | Burkholderiales | Kim et al. (2011) | . | ICNB |
| Paralcyonium | Alcyonacea | Bayer (1981) | Paralcyoniidae. | ICZN |
| Paralelapia | Leucosolenida | Borojevic et al. (2002) | . | ICZN |
| Paralemanea | Batrachospermales | Schneider & Wynne (2007) | . | ICBN |
| Paralembus | Philasterida | Lynn (2008) | . | ICZN |
| Paralemnalia | Alcyonacea | Bayer (1981) | Nephtheidae. | ICZN |
| Paralepistemon | Solanales | Mabberley (2008) | Convolvulaceae. | ICBN |
| Paraleptomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Paraleucilla | Leucosolenida | Borojevic et al. (2002) | . | ICZN |
| Paraleucobryum | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Paralieberkuehnia | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Allogromiidae. | ICZN |
| Paralieberkuhni | | Bass et al. (2009) | Domain Eucarya - Phylum Cercozoa - Class Granofilosea. | ICZN |
| Paraligusticum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Paralineopsis | Heteronemertea | Gibson (1995) | . | ICZN |
| Paralineus | Heteronemertea | Gibson (1995) | . | ICZN |
| Paraliobacillus | Bacillales | Garrity et al. (2005) | . | ICNB |
| Paralipinia | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Parallelostrombidium | Strombidiida | Lynn (2008) | . | ICZN |
| Parallobiopsis | Thalassomycetales | Whisler (1990) | As ellobiopsids. | ICBN |
| Paralomys | Rodentia | Musser & Carleton (2005) | . | ICZN |
| Paralongicollum | Echinorhynchida | Amin et al. (1991) | Pomphorhynchidae. | ICZN |
| Paralophia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Paralovenia | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Paraloxocephalus | Philasterida | Lynn (2008) | . | ICZN |
| Paralueheia | Polymorphida | Saxena & Gupta (2008) | Plagiorhynchinae. | ICZN |
| Paraluffisphaera | Luffisphaerida | Esteban et al. (2005) | . | ICZN |
| Paralychnophora | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Paramachaerium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Paramacrinella | Ichthyophonida | Kirk et al. (2008) | Eccrinales in mycology. | ICZN |
| Paramacrolobium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Paramapania | Poales | Mabberley (2008) | Cyperaceae. | ICBN |
| Paramarteilia | Paramyxida | Bass et al. (2009) | . | ICZN |
| Paramecium | Peniculida | Lynn (2008) | . | ICZN |
| Paramecynostomum | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Paramelhania | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Paramelomys | Rodentia | Musser & Carleton (2005) | . | ICZN |
| Parameria | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Paramesotriton | Caudata | Vitt & Caldwell (2009) | Salamandridae. | ICZN |
| Parametopidium | Armophorida | Lynn (2008) | . | ICZN |
| Paramicrura | Heteronemertea | Gibson (1995) | . | ICZN |
| Paramicrurinella | Heteronemertea | Gibson (1995) | . | ICZN |
| Paramignya | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Paraminutanemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Paramitrella | Urostylida | Lynn (2008) | . | ICZN |
| Paramoeba | Dactylopodida | Rogerson & Patterson (2000); Smirnov et al. (2005) | . | ICZN |
| Paramoebidium | Ichthyophonida | Cafaro (2005) | . | ICZN |
| Paramolgula | Stolidobranchia | Monniot & Monniot (1972) | Molgulidae. | ICZN |
| Paramoltkia | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Paramomitrion | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Paramonas | Pseudodendromonadales | Cavalier-Smith & Chao (2006) | . | ICZN |
| Paramongaia | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Paramoritella | Alteromonadales | Hosoya et al. (2009) | . | ICNB |
| Paramphiporus | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Paramphisiella | Stichotrichida | Lynn (2008) | . | ICZN |
| Paramphitrema | Tectofilosida | Meisterfeld (2000); Cavalier-Smith & Chao (2003) | Amphitremidae. | ICZN |
| Paramucophrya | Endogenida | Lynn (2008) | . | ICZN |
| Paramurexia | Dasyuromorphia | Groves (2005) | . | ICZN |
| Paramuricea | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Paramurrayona | Murrayonida | Vacelet et al. (2002) | . | ICZN |
| Paramyrciaria | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Paramythia | Passeriformes | Clements (2007) | . | ICZN |
| Paramyxa | Paramyxida | Bass et al. (2009) | . | ICZN |
| Paramyxine | Myxiniformes | Nelson (2006) | . | ICZN |
| Paramyxoproteus | Bivalvulida | Lom & Dyková (2006) | . | ICZN |
| Paranactinia | Ceriantharia | Tiffon (1987) | . | ICZN |
| Paranaja | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Paranaperus | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Paranapiacabaea | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Paranassula | Nassulida | Lynn (2008) | . | ICZN |
| Paranecepsia | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Paranemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Paranemertopsis | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Paranemonia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paranephelium | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Paranephelius | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Paraneurachne | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Paranomus | Proteales | Mabberley (2008) | Proteaceae. | ICBN |
| Paranophrys | Philasterida | Lynn (2008) | . | ICZN |
| Paranoplophrya | Astomatida | Lynn (2008) | . | ICZN |
| Paranosema | Microsporida | Sokolova et al. (2003) | . | ICZN |
| Paranotila | Oxymonadida | Brugerolle & Lee (2000) | . | ICZN |
| Parantechinus | Dasyuromorphia | Groves (2005) | . | ICZN |
| Parantennaria | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Parantheopsis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paranthosactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paranthus | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Parantipathes | Antipatharia | Opresko (2002) | . | ICZN |
| Paranucleospora | Microsporida | Nylund et al. (2010) | . | ICZN |
| Paranyctimene | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Paranyctotherus | Clevelandellida | Lynn (2008) | Later synonym of Balantidium?. | ICZN |
| Paraoerskovia | Micrococcales | Khan et al. (2009); Ludwig et al. (2012) | . | ICNB |
| Paraophioidina | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Paraoxychona | Cryptogemmida | Lynn (2008) | . | ICZN |
| Parapantadenia | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Parapedinella | Pedinellales | Sekiguchi et al. (2003) | . | ICBN |
| Parapedobacter | Sphingobacteriales | Kim et al. (2007) | . | ICNB |
| Parapelophryne | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Parapentas | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paraperipatus | Euonychophora | Reid (1996) | Peripatopsidae. | ICZN |
| Paraperlucidibaca | Pseudomonadales | Oh et al. (2011) | . | ICNB |
| Paraperonospora | Peronosporales | Dick (2001); Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Parapetalotricha | Tintinnida | Lynn (2008) | . | ICZN |
| Paraphalaenopsis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Paraphanostoma | Acoela | Dörjes (1968); Faubel & Noreña (2001); Tekle et al. (2005) | Junior synonym of Childia. | ICZN |
| Paraphellia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paraphellia | Actiniaria | Fautin et al. (2007) | Junior homonym, but no replacement name was published. | ICZN |
| Paraphelliactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Paraphilaster | Philasterida | Lynn (2008) | . | ICZN |
| Paraphlomis | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Parapholis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Paraphyllina | Coronatae | Kramp (1961) | . | ICZN |
| Paraphymatoceros | Notothyladales | Renzaglia et al. (2009) | . | ICBN |
| Paraphysomonas | Paraphysomonadales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Paraphysomonadaceae. | ICBN |
| Parapiptadenia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Parapiqueria | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Parapistocalamus | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Paraplagiopyla | Plagiopylida | Lynn (2008) | . | ICZN |
| Parapleistophora | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Parapodinium | | Fensome et al. (1993) | Domain Eucarya - Phylum Dinozoa - Superclass Dinokaryota. | ICBN |
| Parapodium | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Parapodophrya | Exogenida | Lynn (2008) | . | ICZN |
| Parapolia | Heteronemertea | Gibson (1995) | . | ICZN |
| Parapostolepis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Paraprenanthes | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Paraprevotella | Bacteroidales | Morotomi et al. (2009) | . | ICNB |
| Paraproporus | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Paraprorodon | Prorodontida | Lynn (2008) | . | ICZN |
| Paraprosthenorchis | Oligacanthorhynchida | Amin et al. (2008) | Oligacanthorhynchidae. | ICZN |
| Parapteropyrum | Caryophyllales | Mabberley (2008) | Polygonaceae. | ICBN |
| Paraptychostomum | Thigmotrichida | Lynn (2008) | . | ICZN |
| Parapusillimonas | Burkholderiales | Kim et al. (2010) | . | ICNB |
| Parapyxicola | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Paraquadrula | Arcellinida | Meisterfeld (2000) | Difflugina -- Paraquadrulidae. | ICZN |
| Paraquilegia | Ranunculales | Mabberley (2008) | Ranunculaceae. | ICBN |
| Pararaabena | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Pararchidendron | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pararete | Hexactinosida | Reiswig & Wheeler (2002) | . | ICZN |
| Pararhabdophis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pararhacocarpus | Hedwigiales | Goffinet et al. (2009) | . | ICBN |
| Pararhadinaea | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pararhadinorhynchus | Echinorhynchida | Amin (1985) | . | ICZN |
| Pararhaphoxya | Halichondrida | Alvarez & Hooper (2002) | . | ICZN |
| Pararotalia | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Rotaliidae. | ICZN |
| Parartocarpus | Rosales | Mabberley (2008) | Moraceae. | ICBN |
| Pararuellia | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Parasagitta | Aphragmophora | Bieri (1991) | Sagittidae. | ICZN |
| Parasassafras | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Parascalops | Eulipotyphla | McKenna & Bell (1997); Murphy et al. (2001) | . | ICZN |
| Parascaptor | Soricomorpha | Hutterer (2005) | . | ICZN |
| Parascardovia | Bifidobacteriales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Paraschneideria | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Parascon | Parachela | Kinchin (1994) | . | ICZN |
| Parascyllium | Orectolobiformes | Nelson (2006) | . | ICZN |
| Parascyphus | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Parasegetibacter | Sphingobacteriales | Zhang et al. (2009) | . | ICNB |
| Paraseison | Seisonida | Sørensen et al. (2005); Segers (2007) | Dicranophoridae. | ICZN |
| Paraselinum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Paraselliguea | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Parasenecio | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Paraserianthes | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Parashorea | Malvales | Mabberley (2008) | Dipterocarpaceae. | ICBN |
| Parasicuophora | Clevelandellida | Lynn (2008) | . | ICZN |
| Parasicyonis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Parasicyos | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Parasilaus | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Parasimplastrea | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Parasitaxus | Araucariales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Parasonderia | Plagiopylida | Lynn (2008) | . | ICZN |
| Parasopubia | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Parasorites | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Soritidae. | ICZN |
| Paraspadella | Phragmophora | Bieri (1991) | Spadellidae. | ICZN |
| Paraspathidium | Haptorida | Lynn (2008) | . | ICZN |
| Parasphaerastrum | Pterocystida | Mikrjukov et al. (2000)); Cavalier-Smith & von der Heyden (2007); Yabuki et al. (2012) | Heterophryidae. | ICZN |
| Parasphingopyxis | Sphingomonadales | Uchida et al. (2012) | . | ICNB |
| Parasponia | Rosales | Mabberley (2008) | Cannabaceae. | ICBN |
| Parasporobacterium | Clostridiales | Lomans et al. (2001) | . | ICNB |
| Parastemon | Malpighiales | Mabberley (2008) | Chrysobalanaceae. | ICBN |
| Parastempellia | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Parastenella | Alcyonacea | Bayer (1981) | Primnoidae. | ICZN |
| Parastentor | Heterotrichida | Lynn (2008) | . | ICZN |
| Parastephanauge | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Parasterkiella | Sporadotrichida | Küppers et al. (2011) | . | ICZN |
| Parastokesia | Peniculida | Lynn (2008) | Later synonym of Disematostoma?. | ICZN |
| Parastrephia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Parastriga | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Parastrombidinopsis | Choreotrichida | Lynn (2008) | . | ICZN |
| Parastrongylidium | Stichotrichida | Lynn (2008) | . | ICZN |
| Parastygarctus | Arthrotardigrada | Kinchin (1994) | . | ICZN |
| Parastylonychia | Sporadotrichida | Lynn (2008) | . | ICZN |
| Parastylophrya | Endogenida | Lynn (2008) | . | ICZN |
| Parastyrax | Ericales | Mabberley (2008) | Styracaceae. | ICBN |
| Parasutterella | Burkholderiales | Nagai et al. (2009) | . | ICNB |
| Parataeniella | Ichthyophonida | Kirk et al. (2008) | Eccrinales in mycology. | ICZN |
| Paratanarctus | Arthrotardigrada | Kinchin (1994) | . | ICZN |
| Paratealia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Parateclaia | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Paratecoma | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Paratelesto | Alcyonacea | Bayer (1981) | Clavulariidae. | ICZN |
| Paratelmatobius | Anura | Vitt & Caldwell (2009) | Leptodactylidae. | ICZN |
| Paratenuisentis | Neoechinorhynchida | Amin (1985) | . | ICZN |
| Paratetilla | Spirophorida | Van Soest & Rützler (2002) | . | ICZN |
| Paratetrahymena | Philasterida | Lynn (2008) | . | ICZN |
| Paratetramitus | Schizopyrenida | Brown & De Jonckheere (1999); Patterson et al. (2000) | Junior synonym of Tetramitus. | ICZN |
| Parathelohania | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Paratheria | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Parathesis | Ericales | Mabberley (2008) | Primulaceae. | ICBN |
| Parathuiaria | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Paratiara | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Paratimea | Hadromerida | Hooper (2002) | . | ICZN |
| Paratomella | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Paratontonia | Strombidiida | Lynn (2008) | Later synonym of Tontonia?. | ICZN |
| Paratriaina | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paratrichodina | Mobilida | Lynn (2008) | . | ICZN |
| Paratrochammina | Trochamminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Trochamminidae. | ICZN |
| Paratrochilia | Dysteriida | Lynn (2008) | . | ICZN |
| Paratrygon | Myliobatiformes | Nelson (2006) | . | ICZN |
| Paraturbanella | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Paratuzetia | Microsporida | Poddubnaya et al. (2006) | . | ICZN |
| Parauronema | Philasterida | Lynn (2008) | . | ICZN |
| Paraurostyla | Sporadotrichida | Lynn (2008) | . | ICZN |
| Paraurotricha | Prorodontida | Lynn (2008) | . | ICZN |
| Paravahlkampfia | Schizopyrenida | Brown & De Jonckheere (1999) | . | ICZN |
| Paravitex | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Paravorticella | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Parawrightia | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Paraxerus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Parazoanthus | Zoanthidea | Sinniger et al. (2005) | . | ICZN |
| Parazoothamnium | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Parborlasia | Heteronemertea | Gibson (1995) | . | ICZN |
| Pardaliparus | Passeriformes | Clements (2007) | . | ICZN |
| Pardalotus | Passeriformes | Clements (2007) | . | ICZN |
| Pardirallus | Gruiformes | Clements (2007) | . | ICZN |
| Pardofelis | Carnivora | Wozencraft (2005) | . | ICZN |
| Pardoglossum | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Parduczia | Protoheterotrichida | Lynn (2008) | . | ICZN |
| Pareas | Squamata | Vitt & Caldwell (2009); Guo et al. (2011) | Serpentes. Pareatidae. | ICZN |
| Parechiniscus | Echiniscoidea | Kinchin (1994) | . | ICZN |
| Parencentrum | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Parenchymorpha | Nostocales | Hoffmann et al. (2005) | . | ICBN |
| Parentocirrus | Sporadotrichida | Lynn (2008) | . | ICZN |
| Parentodinium | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Parentucellia | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Parepigynum | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Parerenna | Siphonophorae | Bouillon et al. (2006) | . | ICZN |
| Parerythropodium | Alcyonacea | Bayer (1981) | Alcyoniidae. | ICZN |
| Pareuglypha | Euglyphida | Meisterfeld (2000) | . | ICZN |
| Pareugyrioides | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Molgulidae. | ICZN |
| Parhexapodibius | Parachela | Kinchin (1994) | . | ICZN |
| Parhoplophryne | Anura | Vitt & Caldwell (2009) | Microhylidae. | ICZN |
| Pariana | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Parietaria | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Parietichytrium | Thraustochytriales | Yokoyama et al. (2007) | . | ICBN |
| Parietochloris | | Darienko et al. (2010); Neustupa et al. (2011) | Domain Eucarya - Phylum Chlorophyta - Class Trebouxiophyceae. | ICBN |
| Parinari | Malpighiales | Mabberley (2008) | Chrysobalanaceae. | ICBN |
| Paris | Liliales | Mabberley (2008) | Melanthiaceae. | ICBN |
| Parischyronemertes | Eumonostilifera | Chernyshev (2005); Kajihara et al. (2008) | Ototyphlonemertidae. | ICZN |
| Parishia | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Parisia | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Parisis | Alcyonacea | Bayer (1981) | Parisididae. | ICZN |
| Parisoma | Passeriformes | Clements (2007) | . | ICZN |
| Parkerthraustes | Passeriformes | Clements (2007) | . | ICZN |
| Parkia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Parkinsonia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Parlatoria | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Parmaturus | Carcharhiniformes | Nelson (2006) | . | ICZN |
| Parmentiera | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Parmidium | Rhabdomonadales | Leedale (1967); Leedale (2000) | . | ICBN |
| Parmoptila | Passeriformes | Clements (2007) | . | ICZN |
| Parmulina | Arcellinida | Meisterfeld (2000) | Arcellina -- Microcoryciidae. | ICZN |
| Parmursa | Arthrotardigrada | Kinchin (1994) | . | ICZN |
| Parnassia | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Paroaria | Passeriformes | Clements (2007) | . | ICZN |
| Parochetus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Parodia | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Parodianthus | Lamiales | Mabberley (2008) | Verbenaceae. | ICBN |
| Parodiodendron | Malpighiales | Mabberley (2008) | Picrodendraceae. | ICBN |
| Parodiodoxa | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Parodiolyra | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Paroedura | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Parolinia | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Paronychia | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Parophasma | Passeriformes | Clements (2007) | . | ICZN |
| Paropisthopatus | Euonychophora | Reid (1996) | Peripatopsidae. | ICZN |
| Paropsia | Malpighiales | Mabberley (2008) | Passifloraceae. | ICBN |
| Paropsiopsis | Malpighiales | Mabberley (2008) | Passifloraceae. | ICBN |
| Paroreomyza | Passeriformes | Clements (2007) | . | ICZN |
| Parotia | Passeriformes | Clements (2007) | . | ICZN |
| Parotomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Paroxygraphis | Ranunculales | Mabberley (2008) | Ranunculaceae. | ICBN |
| Parrellina | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Elphidiidae. | ICZN |
| Parrelloides | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Parrelloididae. | ICZN |
| Parrina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Parrotia | Saxifragales | Mabberley (2008) | Hamamelidaceae. | ICBN |
| Parrotiopsis | Saxifragales | Mabberley (2008) | Hamamelidaceae. | ICBN |
| Parrya | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Parryella | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Parsonsia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Partenskyella | Chlorarachniales | Ota et al. (2009) | . | ICBN |
| Parthasarathiella | Nostocales | Hoffmann et al. (2005) | . | ICBN |
| Parthenice | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Parthenium | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Parthenocissus | Vitales | Mabberley (2008) | Vitaceae. | ICBN |
| Parula | Passeriformes | Clements (2007) | . | ICZN |
| Parumbrosa | Semaeostomeae | Kramp (1961) | . | ICZN |
| Parundella | Tintinnida | Lynn (2008) | . | ICZN |
| Paruroleptus | Urostylida | Lynn (2008) | Later synonym of Uroleptus?. | ICZN |
| Paruromys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Parurosoma | Sporadotrichida | Lynn (2008) | . | ICZN |
| Parus | Passeriformes | Clements (2007) | . | ICZN |
| Parvamoeba | Himatismenida | Rogerson & Patterson (2000); Cavalier-Smith et al. (2004); Cole et al. (2010); Smirnov et al. (2011) | . | ICZN |
| Parvatia | Ranunculales | Mabberley (2008) | Lardizabalaceae. | ICBN |
| Parvibaculum | Rhizobiales | Schleheck et al. (2004) | . | ICNB |
| Parvicaecilia | Gymnophiona | Vitt & Caldwell (2009) | "Caeciliidae". | ICZN |
| Parvicapsula | Bivalvulida | Lom & Dyková (2006) | . | ICZN |
| Parvicirrus | Heteronemertea | Gibson (1995) | . | ICZN |
| Parvicorbicula | Acanthoecida | Leadbeater & Thomsen (2000) | . | ICZN |
| Parvigenerina | Lituolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pseudobolivinidae. | ICZN |
| Parvilacerta | Squamata | Vitt & Caldwell (2009) | Lacertidae. | ICZN |
| Parvilucifera | Rastrimonadida | Cavalier-Smith & Chao (2004) | . | ICZN |
| Parvimolge | Caudata | Vitt & Caldwell (2009) | Plethodontidae. | ICZN |
| Parvimonas | Clostridiales | Tindall & Euzéby (2006) | Replacement name for Micromonas. | ICNB |
| Parviphycus | Gelidiales | Schneider & Wynne (2007) | . | ICBN |
| Parvoscincus | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Parvularcula | Parvularculales | Garrity et al. (2005) | . | ICNB |
| Pasaccardoa | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pascalia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Paschalococos | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pascherella | Hibberdiales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Chrysocapsaceae (uniflagellate). | ICBN |
| Pascherinema | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Pascopyrum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pasithea | Asparagales | Mabberley (2008) | Hemerocallidaceae. | ICBN |
| Paspalidium | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Paspalum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Passalomyces | Ichthyophonida | Kirk et al. (2008) | Eccrinales in mycology. | ICZN |
| Passer | Passeriformes | Clements (2007) | . | ICZN |
| Passerculus | Passeriformes | Clements (2007) | . | ICZN |
| Passerella | Passeriformes | Clements (2007) | . | ICZN |
| Passerina | Passeriformes | Clements (2007) | . | ICZN |
| Passerina | Malvales | Mabberley (2008) | Thymelaeaceae. | ICBN |
| Passiflora | Malpighiales | Mabberley (2008) | Passifloraceae. | ICBN |
| Pasteurella | Pasteurellales | Garrity et al. (2005) | . | ICNB |
| Pasteuria | Bacillales | Garrity et al. (2005) | . | ICNB |
| Pastinaca | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pastinachus | Myliobatiformes | Nelson (2006) | . | ICZN |
| Pastinacopsis | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pastor | Passeriformes | Clements (2007) | . | ICZN |
| Patagioenas | Columbiformes | Clements (2007) | . | ICZN |
| Patagona | Apodiformes | Clements (2007) | . | ICZN |
| Patagonula | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Patellina | Spirillinida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Patellinidae. | ICZN |
| Patellinella | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Placentulinidae. | ICZN |
| Patellinoides | Spirillinida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Patellinidae. | ICZN |
| Patenocarpus | Nemaliales | Schneider & Wynne (2007) | . | ICBN |
| Patersonia | Asparagales | Mabberley (2008) | Iridaceae. | ICBN |
| Patevia | | Bass et al. (2009) | Domain Eucarya - Phylum Cercozoa - Class Granofilosea. | ICZN |
| Patima | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Patinoa | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Patosia | Poales | Mabberley (2008) | Juncaceae. | ICBN |
| Patrinia | Dipsacales | Mabberley (2008) | Caprifoliaceae. | ICBN |
| Patronella | Choreotrichida | Lynn (2008) | Later synonym of Strombidium?. | ICZN |
| Pattersoniella | Sporadotrichida | Lynn (2008) | . | ICZN |
| Patulibacter | Solirubrobacterales | Takahashi et al. (2006); Reddy & Garcia-Pichel (2009); Ludwig et al. (2012) | . | ICNB |
| Patulophycus | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Paucibacter | Burkholderiales | Rapala et al. (2005) | . | ICNB |
| Paucidentula | Bursovaginoidea | Sørensen (2002) | . | ICZN |
| Paucimonas | Burkholderiales | Garrity et al. (2005) | . | ICNB |
| Paucisalibacillus | Bacillales | Nunes et al. (2006) | . | ICNB |
| Paulamys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pauldopia | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Paulinella | Euglyphida | Meisterfeld (2000) | . | ICZN |
| Paulinum | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Paulisentis | Neoechinorhynchida | Amin (1985) | . | ICZN |
| Paulita | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Paullinia | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Paulownia | Lamiales | Mabberley (2008) | Paulowniaceae. | ICBN |
| Paulsenella | Peridiniales | Fensome et al. (1993); Kühn & Medlin (2005); Levy et al. (2007) | . | ICBN |
| Paulsilvella | Corallinales | Wynne & Schneider (2010) | . | ICBN |
| Paumotua | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Eponididae. | ICZN |
| Pauridia | Asparagales | Mabberley (2008) | Hypoxidaceae. | ICBN |
| Pauridiantha | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paurotricha | Pleuronematida | Alekperov (2009) | . | ICZN |
| Pausandra | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pausinystalia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pauxi | Galliformes | Clements (2007) | . | ICZN |
| Pavetta | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pavieasia | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Pavillardia | Gymnodiniales | Fensome et al. (1993) | . | ICBN |
| Pavlova | Pavlovales | Edvardsen et al. (2000); Jordan et al. (2004) | Pavlovaceae. | ICBN |
| Pavo | Galliformes | Clements (2007) | . | ICZN |
| Pavona | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Pavonina | Buliminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pavoninidae. | ICZN |
| Pavoraja | Rajiformes | Nelson (2006) | . | ICZN |
| Paxistima | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Payena | Ericales | Mabberley (2008) | Sapotaceae. | ICBN |
| Payera | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Paypayrola | Malpighiales | Mabberley (2008) | Violaceae. | ICBN |
| Paysonia | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Peachia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Pearcea | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Pearsonia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pearsonomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pebrilla | Heterotrichida | Lynn (2008) | . | ICZN |
| Pecari | Artiodactyla | Grubb (2005) | . | ICZN |
| Pechuel-Loeschea | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pecluma | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pecteilis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pectenita | Philasterida | Lynn (2008) | . | ICZN |
| Pectinaria | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pectinator | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pectinatus | Selenomonadales | Garrity et al. (2005); Marchandin et al. (2010) | . | ICNB |
| Pectinia | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Pectis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pectispongilla | Haplosclerida | Manconi & Pronzato (2002) | . | ICZN |
| Pectobacterium | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Pectocarya | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pedaliodiscus | Lamiales | Mabberley (2008) | Pedaliaceae. | ICBN |
| Pedalium | Lamiales | Mabberley (2008) | Pedaliaceae. | ICBN |
| Peddiea | Malvales | Mabberley (2008) | Thymelaeaceae. | ICBN |
| Pedersonia | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pedetes | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pedicellarum | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Pedicellina | Coloniales | Emschermann (1972); Nielsen (1982) | Pedicellinidae. | ICZN |
| Pedicellinopsis | Coloniales | Emschermann (1972) | Barentsiidae. | ICZN |
| Pedicellocyathus | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Pedicularis | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Pedilochilus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pedinella | Pedinellales | Moestrup (2000); Sekiguchi et al. (2003) | . | ICBN |
| Pedinomonadopsis | Chloramoebales | Massyuk & Guk (1983) | . | ICBN |
| Pedinomonas | Pedinomonadales | Moestrup (1991); Moestrup (2000) | . | ICBN |
| Pedinopetalum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pedinophyllopsis | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pedinophyllum | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pediocactus | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pediococcus | Lactobacillales | Garrity et al. (2005) | . | ICNB |
| Pediomelum | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pedionomus | Charadriiformes | Clements (2007) | . | ICZN |
| Pedioplanis | Squamata | Vitt & Caldwell (2009) | Lacertidae. | ICZN |
| Pediostomum | Heterotrichida | Lynn (2008) | . | ICZN |
| Pedipartia | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Pedistylis | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Pedobacter | Sphingobacteriales | Garrity et al. (2005) | . | ICNB |
| Pedohymena | Nassulida | Lynn & Small (2000); Lynn (2008); Breiner et al. (2008) | . | ICZN |
| Pedomicrobium | Rhizobiales | Garrity et al. (2005) | . | ICNB |
| Pedospumella | Ochromonadales | Findenig et al. (2010) | . | ICBN |
| Pedostibes | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Peersia | Caryophyllales | Mabberley (2008) | Aizoaceae. | ICBN |
| Pegaeophyton | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pegantha | Narcomedusae | Bouillon et al. (2006) | . | ICZN |
| Peganum | Sapindales | Mabberley (2008) | Nitrariaceae. | ICBN |
| Pegea | Salpida | Godeaux (1998) | . | ICZN |
| Pegia | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pegidia | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pegidiidae. | ICZN |
| Pegmatheca | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Pegolettia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pehria | Myrtales | Mabberley (2008) | Lythraceae. | ICBN |
| Peixotoa | Malpighiales | Mabberley (2008) | Malpighiaceae. | ICBN |
| Pelagacineta | Endogenida | Lynn (2008) | . | ICZN |
| Pelagia | Semaeostomeae | Kramp (1961) | . | ICZN |
| Pelagiana | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pelagibaca | Rhodobacterales | Cho & Giovannoni (2006) | . | ICNB |
| Pelagibacillus | Bacillales | Kim et al. (2007); Krishnamurthi & Chakrabarti (2008) | Later synonym of Terribacillus. | ICNB |
| Pelagibacterium | Rhizobiales | Xu et al. (2011) | . | ICNB |
| Pelagibius | Rhodospirillales | Choi et al. (2009) | . | ICNB |
| Pelagicoccus | Puniceicoccales | Yoon et al. (2007); Yoon et al. (2007) | . | ICNB |
| Pelagicola | Rhodobacterales | Kim et al. (2008) | . | ICNB |
| Pelagococcus | Pelagomonadales | Andersen & Preisig (2000) | . | ICBN |
| Pelagodileptus | Haptorida | Lynn (2008) | . | ICZN |
| Pelagodinium | Suessiales | Siano et al. (2010) | . | ICBN |
| Pelagodoxa | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pelagodroma | Procellariiformes | Clements (2007) | . | ICZN |
| Pelagohalteria | Sporadotrichida | Lynn (2008) | . | ICZN |
| Pelagohydra | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pelagolacrymaria | Haptorida | Lynn (2008) | . | ICZN |
| Pelagomonas | Pelagomonadales | Andersen & Preisig (2000) | . | ICBN |
| Pelagonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Pelagopleura | Appendicularia | Fenaux (1998) | . | ICZN |
| Pelagostrobilidium | Choreotrichida | Lynn (2008) | . | ICZN |
| Pelagostrombidium | Strombidiida | Lynn (2008) | . | ICZN |
| Pelagothrix | Prorodontida | Lynn (2008) | . | ICZN |
| Pelagotrichidium | Stichotrichida | Lynn (2008) | . | ICZN |
| Pelagovasicola | Haptorida | Lynn (2008) | . | ICZN |
| Pelagovorticella | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Pelamis | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Pelargonium | Geraniales | Mabberley (2008) | Geraniaceae. | ICBN |
| Pelargopsis | Coraciiformes | Clements (2007) | . | ICZN |
| Pelatantheria | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pelatractus | Prostomatida | Lynn (2008) | . | ICZN |
| Pelea | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Artiodactyla. | ICZN |
| Pelecanoides | Procellariiformes | Clements (2007) | . | ICZN |
| Pelecanus | Pelecaniformes | Clements (2007) | . | ICZN |
| Pelecostemon | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pelecyamoeba | Arcellinida | Snegovaya & Alekperov (2005) | Difflugiidae. | ICZN |
| Pelecyophrya | Rhynchodida | Lynn (2008) | . | ICZN |
| Pelecyphora | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pelekium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Peleophycus | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Pelexia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Peliaina | | Novarino (2003) | Domain Eucarya - Kingdom Cryptobiontes ? - Phylum Cryptophyta ?. | ICBN |
| Peliosanthes | Asparagales | Mabberley (2008) | Asparagaceae. | ICBN |
| Peliostomum | Lamiales | Mabberley (2008) | Scrophulariaceae. | ICBN |
| Pelistega | Burkholderiales | Garrity et al. (2005) | . | ICNB |
| Pellacalyx | Malpighiales | Mabberley (2008) | Rhizophoraceae. | ICBN |
| Pellaea | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pellegrinia | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pellegriniodendron | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pellia | Pelliales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pelliciera | Ericales | Mabberley (2008) | Tetrameristaceae. | ICBN |
| Pellita | Pellitida | Smirnov et al. (2005); Adl et al. (2005) | Domain Eucarya - Phylum Amoebozoa. | ICZN |
| Pellorneum | Passeriformes | Clements (2007) | . | ICZN |
| Pelmatosphaera | Orthonectida | Stunkard (1982); Kozloff (1992) | Kozloff doubted its affiliation to Orthonectida. | ICZN |
| Pelobacter | Desulfuromonales | Garrity et al. (2005) | . | ICNB |
| Pelobates | Anura | Vitt & Caldwell (2009) | Pelobatidae. | ICZN |
| Pelochelys | Testudinata | Vitt & Caldwell (2009) | Trionychidae. | ICZN |
| Pelocoetes | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Pelodictyon | Chlorobiales | Garrity et al. (2005) | . | ICNB |
| Pelodinium | Odontostomatida | Lynn (2008) | . | ICZN |
| Pelodiscus | Testudinata | Vitt & Caldwell (2009) | Trionychidae. | ICZN |
| Pelodytes | Anura | Vitt & Caldwell (2009) | Pelodytidae. | ICZN |
| Pelomedusa | Testudinata | Vitt & Caldwell (2009) | Pelomedusidae. | ICZN |
| Pelomonas | Burkholderiales | Xie & Yokota (2005) | . | ICNB |
| Pelomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pelomyxa | Pelobiontida | Brugerolle & Patterson (2000); Cavalier-Smith et al. (2004) | . | ICZN |
| Pelonaia | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Styelidae. | ICZN |
| Pelophila | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Pelophryne | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Pelophylax | Anura | Vitt & Caldwell (2009) | Ranidae. | ICZN |
| Pelosina | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Astrorhizidae. | ICZN |
| Pelosinus | Selenomonadales | Shelobolina et al. (2007); Marchandin et al. (2010) | . | ICNB |
| Pelospora | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Pelotomaculum | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Peltacineta | Endogenida | Lynn (2008) | . | ICZN |
| Peltaea | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Peltandra | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Peltaria | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Peltariopsis | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Peltasta | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Peltastes | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Peltastisis | Alcyonacea | Bayer (1981) | Isididae. | ICZN |
| Pelticalyx | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Peltiera | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Peltoboykinia | Saxifragales | Mabberley (2008) | Saxifragaceae. | ICBN |
| Peltocalathos | Ranunculales | Mabberley (2008) | Ranunculaceae. | ICBN |
| Peltocephalus | Testudinata | Vitt & Caldwell (2009) | Podocnemidae. | ICZN |
| Peltodon | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Peltogyne | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Peltohyas | Charadriiformes | Clements (2007) | . | ICZN |
| Peltolepis | Marchantiales | Crandall-Stotler et al. (2009) | . | ICBN |
| Peltomonas | | Kristiansen & Preisig (2001) | Domain Eucarya - Kingdom Straminipila - Phylum Ochrophyta. | ICBN |
| Peltomyces | Plasmodiophorida | Kirk et al. (2008) | . | ICZN |
| Peltophorum | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Peltophryne | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Peltophyllum | Pandanales | Mabberley (2008) | Triuridaceae. | ICBN |
| Peltops | Passeriformes | Clements (2007) | . | ICZN |
| Peltostigma | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pelucha | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pelusios | Testudinata | Vitt & Caldwell (2009) | Pelomedusidae. | ICZN |
| Pemphis | Myrtales | Mabberley (2008) | Lythraceae. | ICBN |
| Penaea | Myrtales | Mabberley (2008) | Crypteroniaceae. | ICBN |
| Penardeugenia | Tectofilosida | Meisterfeld (2000); Cavalier-Smith & Chao (2003) | Chlamydophryidae. | ICZN |
| Penardia | Aconchulinida | Bass et al. (2009) | . | ICZN |
| Penardiella | Haptorida | Lynn (2008) | . | ICZN |
| Penardochlamys | Arcellinida | Meisterfeld (2000) | Arcellina -- Microcoryciidae. | ICZN |
| Penardogromia | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Allogromiidae. | ICZN |
| Penares | Astrophorida | Uriz (2002) | . | ICZN |
| Pendonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Pendulomonas | Placidiales | Cavalier-Smith & Chao (2006) | . | ICZN |
| Pendulothecium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Penelope | Galliformes | Clements (2007) | . | ICZN |
| Penelopeia | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Penelopides | Coraciiformes | Clements (2007) | . | ICZN |
| Penelopina | Galliformes | Clements (2007) | . | ICZN |
| Peneothello | Passeriformes | Clements (2007) | . | ICZN |
| Peneroplis | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Peneroplidae. | ICZN |
| Penianthus | Ranunculales | Mabberley (2008) | Menispermaceae. | ICBN |
| Peniculistoma | Pleuronematida | Lynn (2008) | . | ICZN |
| Peniocereus | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Penium | Desmidiales | Gontcharov (2008) | . | ICBN |
| Pennantia | Apiales | Mabberley (2008) | Pennantiaceae. | ICBN |
| Pennaria | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pennatula | Pennatulacea | Williams (1995) | . | ICZN |
| Pennellia | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pennellianthus | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Pennilabium | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pennisetum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Penopactis | Ceriantharia | Tiffon (1987) | . | ICZN |
| Penstemon | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Pentabrachion | Malpighiales | Mabberley (2008) | Phyllanthaceae. | ICBN |
| Pentacalia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pentacapsula | Multivalvulida | Lom & Dyková (2006) | . | ICZN |
| Pentace | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pentaceras | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pentachaeta | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pentachlaena | Malvales | Mabberley (2008) | Sarcolaenaceae. | ICBN |
| Pentachondra | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pentaclethra | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pentactinia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Pentacyphus | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentadenia | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Pentadesma | Malpighiales | Mabberley (2008) | Guttiferae. | ICBN |
| Pentadiplandra | Brassicales | Mabberley (2008) | Pentadiplandraceae. | ICBN |
| Pentaglottis | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pentagonanthus | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentagonia | Arcellinida | Meisterfeld (2000) | Difflugina -- Difflugiidae. | ICZN |
| Pentagonia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pentagramma | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pentahymena | Bursariomorphida | Lynn (2008); Foissner et al. (2011) | . | ICZN |
| Pentalagus | Lagomorpha | McKenna & Bell (1997) | . | ICZN |
| Pentalamina | Parmales | Booth & Marchant (1987) | . | ICBN |
| Pentalepis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pentalinon | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentaloncha | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pentameris | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pentamerista | Ericales | Mabberley (2008) | Tetrameristaceae. | ICBN |
| Pentamonas | Sphenomonadales | Leedale (1967) | Possibly related to Petalomonas. | ICBN |
| Pentanchus | Carcharhiniformes | Nelson (2006) | . | ICZN |
| Pentanema | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pentanisia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pentanopsis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pentanura | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentapetes | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pentapharsodinium | Peridiniales | Fensome et al. (1993) | . | ICBN |
| Pentaphragma | Asterales | Mabberley (2008) | Pentaphragmataceae. | ICBN |
| Pentaphylax | Ericales | Mabberley (2008) | Pentaphylacaceae. | ICBN |
| Pentaplaris | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pentapleura | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pentapogon | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pentaptilon | Asterales | Mabberley (2008) | Goodeniaceae. | ICBN |
| Pentarhopalopilia | Santalales | Mabberley (2008) | Opiliaceae. | ICBN |
| Pentarrhinum | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentas | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pentasacme | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentaschistis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pentascyphus | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Pentaspadon | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pentastelma | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentastemona | Pandanales | Mabberley (2008) | Stemonaceae. | ICBN |
| Pentastemonodiscus | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pentastichella | Orthotrichales | Goffinet et al. (2009) | . | ICBN |
| Pentatheca | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Pentatrichia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pentatrichomonas | Trichomonadida | Cepicka et al. (2010) | . | ICZN |
| Pentatrichomonoides | Trichomonadida | Cepicka et al. (2010) | . | ICZN |
| Pentatrocha | Flosculariaceae | Segers & Shiel (2008) | Flosculariidae. | ICZN |
| Pentatropis | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Penthetor | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Penthorum | Saxifragales | Mabberley (2008) | Saxifragaceae. | ICBN |
| Pentodon | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pentopetia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pentstemonacanthus | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pentzia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Penzigiella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Peperomia | Piperales | Mabberley (2008) | Piperaceae. | ICBN |
| Peplidium | Lamiales | Mabberley (2008) | Phrymaceae. | ICBN |
| Peplonia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Peponium | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Peponocephala | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Cetacea. | ICZN |
| Peponocyathus | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Peponopsis | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Peptococcus | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Peptoniphilus | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Peptostreptococcus | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Pera | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Peracarpa | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Peradorcas | Australidelphia | McKenna & Bell (1997); Groves (2005) | Later synonym of Petrogale. | ICZN |
| Perakanthus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Perama | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Perameles | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Peranema | Heteronematales | Leedale (1967); Larsen & Patterson (1991); Leedale (2000) | Later homonym under ICBN. Synonymous to Pseudoperanema. | ICBN |
| Peranema | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Peranemopsis | Heteronematales | Leedale (1967) | . | ICBN |
| Peraxilla | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Percnostola | Passeriformes | Clements (2007) | . | ICZN |
| Percolomonas | Percolomonadida | Cavalier-Smith (2003) | . | ICZN |
| Percultazonaria | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Vaginulinidae. | ICZN |
| Perdicium | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Perdicula | Galliformes | Clements (2007) | . | ICZN |
| Perdix | Galliformes | Clements (2007) | . | ICZN |
| Perdusenia | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Perebea | Rosales | Mabberley (2008) | Moraceae. | ICBN |
| Peredibacter | Bdellovibrionales | Davidov & Jurkevitch (2004) | . | ICNB |
| Peregrina | Malpighiales | Mabberley (2008) | Malpighiaceae. | ICBN |
| Peregrinia | Thaumatomonadida | Howe et al. (2011) | . | ICZN |
| Perenideboles | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pereskia | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pereskiopsis | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Perexilibacter | Cytophagales | Yoon et al. (2007); Ludwig et al. (2011) | . | ICNB |
| Perezella | Apostomatida | Lynn (2008) | . | ICZN |
| Perezia | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Perezia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pergularia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Periacineta | Evaginogenida | Lynn (2008) | . | ICZN |
| Periandra | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Perianthomega | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Periballia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pericallis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pericalymma | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Pericalypta | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pericampylus | Ranunculales | Mabberley (2008) | Menispermaceae. | ICBN |
| Pericaryon | Apostomatida | Lynn (2008) | . | ICZN |
| Perichaena | Trichiales | Yamamoto (1998) | . | ICBN |
| Pericharax | Clathrinida | Borojevic et al. (2002) | . | ICZN |
| Perichlaena | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Pericolpa | Coronatae | Kramp (1961) | . | ICZN |
| Pericome | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pericopsis | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pericrocotus | Passeriformes | Clements (2007) | . | ICZN |
| Perideridia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Peridictyon | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Peridiniella | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Peridiniopsis | Peridiniales | Fensome et al. (1993); Trigueros (2000) | Now checking. | ICBN |
| Peridinium | Peridiniales | Fensome et al. (1993) | . | ICBN |
| Peridion | | Lynn (2008) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora - Class Prostomatea. | ICZN |
| Peridionella | | Lynn (2008) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora - Class Prostomatea. | ICZN |
| Peridiscophrys | Evaginogenida | Lynn (2008) | . | ICZN |
| Peridiscus | Saxifragales | Mabberley (2008) | Peridiscaceae. | ICBN |
| Perifolliculina | Heterotrichida | Lynn (2008) | . | ICZN |
| Perigonella | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Periholosticha | Urostylida | Lynn (2008) | . | ICZN |
| Perikladosporon | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Perilla | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Perillula | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Perinema | | Schneider & Wynne (2007) | . | ICBN |
| Periparus | Passeriformes | Clements (2007) | . | ICZN |
| Peripatoides | Euonychophora | Reid (1996) | Peripatopsidae. | ICZN |
| Peripatopsis | Euonychophora | Reid (1996) | Peripatopsidae. | ICZN |
| Peripatus | Euonychophora | Peck (1975) | Peripatidae. | ICZN |
| Peripentadenia | Oxalidales | Mabberley (2008) | Elaeocarpaceae. | ICBN |
| Peripeplus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Periphragella | Hexactinosida | Reiswig & Wheeler (2002) | . | ICZN |
| Periphykon | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Periphylla | Coronatae | Kramp (1961) | . | ICZN |
| Periphyllopsis | Coronatae | Kramp (1961) | . | ICZN |
| Peripleura | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Periploca | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Periporphyrus | Passeriformes | Clements (2007) | . | ICZN |
| Periptera | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Peripterygia | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Periptygma | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Allogromiidae. | ICZN |
| Peripyramis | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Perischelia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Perisincirra | Urostylida | Lynn (2008) | . | ICZN |
| Perisoreus | Passeriformes | Clements (2007) | . | ICZN |
| Perispira | Haptorida | Lynn (2008) | . | ICZN |
| Perissocarpa | Malpighiales | Mabberley (2008) | Ochnaceae. | ICBN |
| Perissocephalus | Passeriformes | Clements (2007) | . | ICZN |
| Perissocoeleum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Perissonemertes | Heteronemertea | Gibson (1995) | . | ICZN |
| Peristeranthus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Peristeria | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Peristrombidium | Strombidiida | Lynn (2008) | . | ICZN |
| Peristrophe | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Peristylus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Peritassa | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Perithamnion | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Peritromus | Heterotrichida | Lynn (2008) | . | ICZN |
| Perityle | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Perkinsiella | Prokinetoplastida | Moreira et al. (2004); Özdikmen (2009) | Junior homonym. Substituted by Hollandeia. | ICZN |
| Perkinsus | Perkinsida | Cavalier-Smith & Chao (2004) | . | ICZN |
| Perlucidibaca | Pseudomonadales | Song et al. (2008) | . | ICNB |
| Pernicivesicula | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Pernina | Schizopyrenida | Patterson et al. (2000) | . | ICZN |
| Pernis | Falconiformes | Clements (2007) | . | ICZN |
| Perochirus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Perodicticus | Primates | McKenna & Bell (1997) | . | ICZN |
| Perofascia | Peronosporales | Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Perognathus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Peromelissa | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Peromyscus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Peronanthus | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Perone | Mischococcales | Ettl (1978) | . | ICBN |
| Peronema | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Peroniella | Mischococcales | Ettl (1978) | . | ICBN |
| Peronophythora | Pythiales | Dick (2001); Kirk et al. (2008) | Pythiaceae. | ICBN |
| Peronosclerospora | Peronosporales | Dick (2001); Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Peronospora | Peronosporales | Dick (2001); Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Perophora | Phlebobranchia | Monniot & Monniot (1972); Monniot (2001) | Perophoridae. | ICZN |
| Peropteryx | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Peroryctes | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Perotis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Perovskia | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Perralderia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Perriera | Sapindales | Mabberley (2008) | Simaroubaceae. | ICBN |
| Perrierbambus | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Perrieriella | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Perrierodendron | Malvales | Mabberley (2008) | Sarcolaenaceae. | ICBN |
| Perrierophytum | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Perrierosedum | Saxifragales | Mabberley (2008) | Crassulaceae. | ICBN |
| Perrinia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Perrottetia | Huerteales | Mabberley (2008) | Dipentodontaceae. | ICBN |
| Perryodendron | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Persa | Trachymedusae | Bouillon et al. (2006) | . | ICZN |
| Persea | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Perseia | Astomatida | Lynn (2008) | . | ICZN |
| Persephonella | Aquificales | Garrity et al. (2005) | . | ICNB |
| Persicaria | Caryophyllales | Mabberley (2008) | Polygonaceae. | ICBN |
| Persicirhabdus | Verrucomicrobiales | Yoon et al. (2008) | . | ICNB |
| Persicitalea | Cytophagales | Yoon et al. (2007); Ludwig et al. (2011) | . | ICNB |
| Persicivirga | Flavobacteriales | O'Sullivan et al. (2006) | . | ICNB |
| Persicobacter | Cytophagales | Garrity et al. (2005); Ludwig et al. (2011) | . | ICNB |
| Persoonia | Proteales | Mabberley (2008) | Proteaceae. | ICBN |
| Perssonia | Bryales | Goffinet et al. (2009) | . | ICBN |
| Perssoniella | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pertusadina | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pertya | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pervillea | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Perymenium | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pescatoria | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pescozoon | Stichotrichida | Lynn (2008) | . | ICZN |
| Pessonella | Vannellida | Rogerson & Patterson (2000); Smirnov et al. (2005) | . | ICZN |
| Petagnaea | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Petalacte | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Petalactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Petaladenium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Petalidium | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Petalodinium | Noctilucales | Fensome et al. (1993) | . | ICBN |
| Petalomonas | Sphenomonadales | Leedale (1967); Leedale (2000) | . | ICBN |
| Petalonema | Nostocales | Hoffmann et al. (2005) | . | ICBN |
| Petalonyx | Cornales | Mabberley (2008) | Loasaceae. | ICBN |
| Petalophyllum | Fossombroniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Petalostelma | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Petalostigma | Malpighiales | Mabberley (2008) | Picrodendraceae. | ICBN |
| Petalostylis | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Petalotricha | Tintinnida | Lynn (2008) | . | ICZN |
| Petasaria | Prymnesiales | Yoshida et al. (2006) | Prymnesiaceae. | ICBN |
| Petasiella | Trachymedusae | Bouillon et al. (2006) | . | ICZN |
| Petasites | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Petasus | Trachymedusae | Bouillon et al. (2006) | . | ICZN |
| Petaurillus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Petaurista | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Petauroides | Diprotodontia | Groves (2005) | . | ICZN |
| Petaurus | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Petchia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Petelotiella | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Petenaea | Huerteales | Mabberley (2008); Christenhusz et al. (2010) | Petenaeaceae. | ICBN |
| Peteravenia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Peteria | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Petermannia | Liliales | Mabberley (2008) | Petermanniaceae. | ICBN |
| Peterodendron | Malpighiales | Mabberley (2008) | Achariaceae. | ICBN |
| Petersenia | | Dick (2001); Kirk et al. (2008) | Domain Eucarya - Kingdom Straminipila - Phylum Oomycota. Pontismataceae. | ICBN |
| Petersianthus | Ericales | Mabberley (2008) | Lecythidaceae. | ICBN |
| Petinomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Petitia | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Petitiocodon | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Petitmenginia | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Petiveria | Caryophyllales | Mabberley (2008) | Phytolaccaceae. | ICBN |
| Petopentia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Petracola | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Petradoria | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Petraeomyrtus | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Petraeovitex | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Petrea | Lamiales | Mabberley (2008) | Verbenaceae. | ICBN |
| Petrimonas | Bacteroidales | Grabowski et al. (2005) | . | ICNB |
| Petrobacter | Hydrogenophilales | Bonilla Salinas et al. (2004) | . | ICNB |
| Petrobiona | Lithonida | Vacelet et al. (2002) | . | ICZN |
| Petrobium | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Petrocallis | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Petrochelidon | Passeriformes | Clements (2007) | . | ICZN |
| Petrocodon | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Petrocosmea | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Petrodromus | Macroscelidea | McKenna & Bell (1997) | . | ICZN |
| Petroedmondia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Petrogale | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Petroglossum | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Petrohua | Batrachospermales | Schneider & Wynne (2007) | . | ICBN |
| Petroica | Passeriformes | Clements (2007) | . | ICZN |
| Petromarula | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Petromica | | Pisera & Lévi (2002) | Domain Eucarya - Kingdom Animalia - Phylum Porifera - Class Demospongiae (lithistids) Desmanthidae. | ICZN |
| Petromus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Petromyscus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Petromyzon | Petromyzontiformes | Nelson (2006) | . | ICZN |
| Petronia | Passeriformes | Clements (2007) | . | ICZN |
| Petronymphe | Asparagales | Mabberley (2008) | Asparagaceae. | ICBN |
| Petropedetes | Anura | Vitt & Caldwell (2009) | Petropedetidae. | ICZN |
| Petrophassa | Columbiformes | Clements (2007) | . | ICZN |
| Petrophile | Proteales | Mabberley (2008) | Proteaceae. | ICBN |
| Petrophytum | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Petropseudes | Diprotodontia | Groves (2005) | . | ICZN |
| Petroravenia | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Petrorhagia | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Petrosaspongia | Dictyoceratida | Cook & Bergquist (2002) | . | ICZN |
| Petrosaurus | Squamata | Vitt & Caldwell (2009) | Iguanidae. | ICZN |
| Petrosavia | Petrosaviales | Mabberley (2008) | Petrosaviaceae. | ICBN |
| Petroselinum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Petrosia | Haplosclerida | Desqueyroux-Faúndez & Valentine (2002) | . | ICZN |
| Petrosimonia | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Petrostroma | Lithonida | Vacelet et al. (2002) | . | ICZN |
| Petrotoga | Thermotogales | Garrity et al. (2005) | . | ICNB |
| Petteria | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Petunia | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Peucedanum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Peucedramus | Passeriformes | Clements (2007) | . | ICZN |
| Peucephyllum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Peumus | Laurales | Mabberley (2008) | Monimiaceae. | ICBN |
| Peyssonnelia | Peyssonneliales | Schneider & Wynne (2007); Krayesky et al. (2009) | . | ICBN |
| Peyssonneliopsis | Nemastomatales | Wynne & Schneider (2010) | . | ICBN |
| Pezopetes | Passeriformes | Clements (2007) | . | ICZN |
| Pezoporus | Psittaciformes | Clements (2007) | . | ICZN |
| Pfaffia | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pfeiffera | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pfeifferinella | Eucoccidiorida | Perkins et al. (2000) | . | ICZN |
| Pfennigia | Chromatiales | Garrity et al. (2005) | . | ICNB |
| Pfiesteria | Peridiniales | Dodge & Lee (2000); Litaker et al. (2005) | . | ICBN |
| Pfitzeria | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Phacelia | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Phacellanthus | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Phacellaria | Santalales | Mabberley (2008) | Santalaceae. | ICBN |
| Phacellodomus | Passeriformes | Clements (2007) | . | ICZN |
| Phacellophora | Semaeostomeae | Kramp (1961) | . | ICZN |
| Phacellothrix | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phacelocarpus | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Phacelocyathus | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Phacelophrynium | Zingiberales | Mabberley (2008) | Marantaceae. | ICBN |
| Phacelurus | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phacochoerus | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Artiodactyla. | ICZN |
| Phacodinium | Phacodiniida | Lynn (2008) | . | ICZN |
| Phacomonas | Chloramoebales | Ettl (1978) | . | ICBN |
| Phacus | Euglenales | Leedale (1967); Leedale (2000); Marin et al. (2003) | . | ICBN |
| Phaeanthus | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Phaeaster | Hibberdiales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Chrysocapsaceae (uniflagellate). | ICBN |
| Phaedranassa | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Phaenanthoecium | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phaenicophaeus | Cuculiformes | Clements (2007) | . | ICZN |
| Phaenicophilus | Passeriformes | Clements (2007) | . | ICZN |
| Phaenocoma | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phaenomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Phaenosperma | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phaenostictus | Passeriformes | Clements (2007) | . | ICZN |
| Phaeobacter | Rhodobacterales | Martens et al. (2006) | . | ICNB |
| Phaeobotrys | | Bailey et al. (1998); Maistro et al. (2009) | Domain Eucarya - Kingdom Straminipila - Phylum Ochrophyta. Closely related to Pleurochloridella. | ICBN |
| Phaeoceros | Notothyladales | Renzaglia et al. (2009) | . | ICBN |
| Phaeochroa | Apodiformes | Clements (2007) | . | ICZN |
| Phaeochromatium | Chromatiales | Shivali et al. (2012) | . | ICNB |
| Phaeocolax | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Phaeocystis | Phaeocystales | Edvardsen et al. (2000); Jordan et al. (2004) | Phaeocystaceae. | ICBN |
| Phaeodactylis | Phaeogymnocellida | Takahashi & Anderson (2000) | . | ICZN |
| Phaeodermatium | | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Domain Eucarya - Kingdom Straminipila - Phylum Ochrophyta - Class Chrysophyceae. Hydruraceae. | ICBN |
| Phaeodina | Phaeogymnocellida | Takahashi & Anderson (2000) | . | ICZN |
| Phaeogloea | Phaeothamniales | Bailey et al. (1998) | . | ICBN |
| Phaeognathus | Caudata | Vitt & Caldwell (2009) | Plethodontidae. | ICZN |
| Phaeolejeunea | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Phaeomegaceros | Dendrocerotales | Renzaglia et al. (2009) | . | ICBN |
| Phaeomonas | Pinguiochrysidales | Kawachi et al. (2002) | . | ICBN |
| Phaeomyias | Passeriformes | Clements (2007) | . | ICZN |
| Phaeonychium | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Phaeoplaca | Chromulinales | Kristiansen & Preisig (2001) | Chrysothallaceae (uniflagellate). | ICBN |
| Phaeoptilum | Caryophyllales | Mabberley (2008) | Nyctaginaceae. | ICBN |
| Phaeopyla | Phaeogymnocellida | Takahashi & Anderson (2000) | . | ICZN |
| Phaeosaccion | Chrysomeridales | Preisig (1995) | . | ICBN |
| Phaeoschizochlamys | Phaeothamniales | Bailey et al. (1998) | . | ICBN |
| Phaeosphaera | Phaeogymnocellida | Takahashi & Anderson (2000) | . | ICZN |
| Phaeosphaera | Hibberdiales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Chrysocapsaceae (no flagellate stage). | ICBN |
| Phaeospirillum | Rhodospirillales | Garrity et al. (2005) | . | ICNB |
| Phaeostigma | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phaeothamnion | Phaeothamniales | Bailey et al. (1998) | . | ICBN |
| Phaeovibrio | Rhodospirillales | Lakshmi et al. (2011) | . | ICNB |
| Phaethon | Pelecaniformes | Clements (2007) | . | ICZN |
| Phaethornis | Apodiformes | Clements (2007) | . | ICZN |
| Phaetusa | Charadriiformes | Clements (2007) | . | ICZN |
| Phagnalon | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phagodinium | Phagodinida | Cavalier-Smith & Chao (2004) | . | ICZN |
| Phagomyxa | Phagomyxida | Cavalier-Smith (1993); Kirk et al. (2008); Bass et al. (2009) | . | ICZN |
| Phagoon | Nassulida | Lynn & Small (2000); Lynn (2008); Breiner et al. (2008) | . | ICZN |
| Phainantha | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Phainogullmia | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Allogromiidae. | ICZN |
| Phainopepla | Passeriformes | Clements (2007) | . | ICZN |
| Phainoptila | Passeriformes | Clements (2007) | . | ICZN |
| Phaiomys | Rodentia | Musser & Carleton (2005) | . | ICZN |
| Phaius | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Phakellia | Halichondrida | Alvarez & Hooper (2002) | . | ICZN |
| Phakettia | Halichondrida | Van Soest et al. (2002) | . | ICZN |
| Phalacrachena | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phalacraea | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phalacrocarpum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phalacrocleptes | Exogenida | Lynn (2008) | . | ICZN |
| Phalacrocorax | Pelecaniformes | Clements (2007) | . | ICZN |
| Phalacroseris | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phalaenopsis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Phalaenoptilus | Caprimulgiformes | Clements (2007) | . | ICZN |
| Phalanger | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Phalangopora | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Phalansterium | Phalansteriida | Cavalier-Smith et al. (2004) | . | ICZN |
| Phalaris | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phalaropus | Charadriiformes | Clements (2007) | . | ICZN |
| Phalcoboenus | Falconiformes | Clements (2007) | . | ICZN |
| Phaleria | Malvales | Mabberley (2008) | Thymelaeaceae. | ICBN |
| Phallocephale | Euonychophora | Reid (1996) | Peripatopsidae. | ICZN |
| Phallonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Phallusia | Phlebobranchia | Monniot & Monniot (1972); Monniot (2001) | Ascidiidae. | ICZN |
| Phalodinium | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Phalotris | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Phaner | Primates | McKenna & Bell (1997) | . | ICZN |
| Phanera | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Phanerobia | Neobodonida | von der Heyden et al. (2004) | Later synonym of Dimastigella. | ICZN |
| Phanerodiscus | Santalales | Mabberley (2008) | Olacaceae. | ICBN |
| Phaneroglossa | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phanerophlebia | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Phanerosorus | Gleicheniales | Christenhusz et al. (2011) | . | ICBN |
| Phania | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phanopathes | Antipatharia | Opresko (2004) | . | ICZN |
| Phanopyrum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phapitreron | Columbiformes | Clements (2007) | . | ICZN |
| Phaps | Columbiformes | Clements (2007) | . | ICZN |
| Pharnaceum | Caryophyllales | Mabberley (2008) | Molluginaceae. | ICBN |
| Pharomachrus | Trogoniformes | Clements (2007) | . | ICZN |
| Pharotis | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Pharus | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pharyngia | Acoela | Nilsson et al. (2011) | . | ICZN |
| Pharyngodictyon | Aplousobranchia | Monniot & Monniot (1972) | Polyclinidae. | ICZN |
| Pharyngomonas | Pharyngomonadida | Cavalier-Smith & Nikolaev (2008) | . | ICZN |
| Phascogale | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Phascolarctobacterium | Selenomonadales | Garrity et al. (2005); Marchandin et al. (2010) | . | ICNB |
| Phascolarctos | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Phascolodon | Chlamydodontida | Lynn (2008) | . | ICZN |
| Phascolosorex | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Phascomurexia | Dasyuromorphia | Groves (2005) | . | ICZN |
| Phascopsis | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Phascum | Pottiales | Werner et al. (2004) | . | ICBN |
| Phaselicystis | Myxococcales | Garcia et al. (2009) | . | ICNB |
| Phaseolus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Phasianus | Galliformes | Clements (2007) | . | ICZN |
| Phasmahyla | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Phataginus | Pholidota | McKenna & Bell (1997); Schlitter (2005) | Later synonym of Manis. | ICZN |
| Phatnacantha | Arthracanthida | Febvre et al. (2000) | . | ICZN |
| Phaulomys | Rodentia | McKenna & Bell (1997); Musser & Carleton (2005) | Later synonym of Myodes. | ICZN |
| Phaulopsis | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Phaulothamnus | Caryophyllales | Mabberley (2008) | Achatocarpaceae. | ICBN |
| Phebalium | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Phedina | Passeriformes | Clements (2007) | . | ICZN |
| Phegopteris | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Phegornis | Charadriiformes | Clements (2007) | . | ICZN |
| Pheidochloa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pheidonocarpa | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Phellia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phelliactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phelline | Asterales | Mabberley (2008) | Phellinaceae. | ICBN |
| Phelliogeton | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phellocalyx | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phellodendron | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Phelloderma | Poecilosclerida | Van Soest & Hajdu (2002) | . | ICZN |
| Phellolophium | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Phelpsia | Passeriformes | Clements (2007) | . | ICZN |
| Phelpsiella | Poales | Mabberley (2008) | Rapateaceae. | ICBN |
| Phelsuma | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Phelypaea | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Phemeranthus | Caryophyllales | Mabberley (2008) | Portulacaceae. | ICBN |
| Phenacomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Phenakospermum | Zingiberales | Mabberley (2008) | Strelitziaceae. | ICBN |
| Phenax | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Phenylobacterium | Caulobacterales | Garrity et al. (2005) | . | ICNB |
| Pheopolykrikos | Gymnodiniales | Fensome et al. (1993) | . | ICBN |
| Pherohapsis | Anura | Vitt & Caldwell (2009) | Microhylidae. | ICZN |
| Pheronema | Amphidiscosida | Tabachnick & Menshenina (2002) | . | ICZN |
| Pheroneonemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Pherosphaera | Araucariales | Farjon (2001); Mabberley (2008); Eckenwalder (2009); Christenhusz et al. (2011) | . | ICBN |
| Pherotrichis | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pheucticus | Passeriformes | Clements (2007) | . | ICZN |
| Phialacanthus | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Phialanthus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phialella | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Phialina | Haptorida | Lynn (2008) | . | ICZN |
| Phialinides | Haptorida | Lynn (2008) | . | ICZN |
| Phialoba | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phialoides | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Phialopsis | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Phialucium | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Phibalura | Passeriformes | Clements (2007) | . | ICZN |
| Phigys | Psittaciformes | Clements (2007) | . | ICZN |
| Philachoerus | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Philacra | Malpighiales | Mabberley (2008) | Ochnaceae. | ICBN |
| Philactinoposthia | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Philactis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Philadelphus | Cornales | Mabberley (2008) | Hydrangeaceae. | ICBN |
| Philander | Ameridelphia | McKenna & Bell (1997) | . | ICZN |
| Philantomba | Artiodactyla | Grubb (2005) | . | ICZN |
| Philaster | Philasterida | Lynn (2008) | . | ICZN |
| Philasterides | Philasterida | Lynn (2008) | . | ICZN |
| Philautus | Anura | Vitt & Caldwell (2009) | Rhacophoridae. | ICZN |
| Philbornea | Malpighiales | Mabberley (2008) | Linaceae. | ICBN |
| Philcoxia | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Philemon | Passeriformes | Clements (2007) | . | ICZN |
| Philenoptera | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Philentoma | Passeriformes | Clements (2007) | . | ICZN |
| Philepitta | Passeriformes | Clements (2007) | . | ICZN |
| Philesia | Liliales | Mabberley (2008) | Philesiaceae. | ICBN |
| Philesturnus | Passeriformes | Clements (2007) | . | ICZN |
| Philetairus | Passeriformes | Clements (2007) | . | ICZN |
| Philetor | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Philgamia | Malpighiales | Mabberley (2008) | Malpighiaceae. | ICBN |
| Philippiella | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Phillyrea | Lamiales | Mabberley (2008) | Oleaceae. | ICBN |
| Philocelis | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Philochortus | Squamata | Vitt & Caldwell (2009) | Lacertidae. | ICZN |
| Philodendron | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Philodice | Poales | Mabberley (2008) | Eriocaulaceae. | ICBN |
| Philodina | Bdelloida | Segers (2002); Segers (2007) | . | ICZN |
| Philodinavus | Bdelloida | Segers (2002); Segers (2007) | . | ICZN |
| Philodryas | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Philoglossa | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Philohydor | Passeriformes | Clements (2007) | . | ICZN |
| Philomachus | Charadriiformes | Clements (2007) | . | ICZN |
| Philomecynostomum | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Philomedusa | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Philonotis | Bartramiales | Goffinet et al. (2009) | . | ICBN |
| Philophyllum | Hookeriales | Goffinet et al. (2009) | . | ICBN |
| Philoria | Anura | Vitt & Caldwell (2009) | Limnodynastidae. | ICZN |
| Philortyx | Galliformes | Clements (2007) | . | ICZN |
| Philothamnus | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Philotheca | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Philydor | Passeriformes | Clements (2007) | . | ICZN |
| Philydrella | Commelinales | Mabberley (2008) | Philydraceae. | ICBN |
| Philydrum | Commelinales | Mabberley (2008) | Philydraceae. | ICBN |
| Philyra | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Philyrophyllum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phimophis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Phimosus | Ciconiiformes | Clements (2007) | . | ICZN |
| Phinaea | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Phippsia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phitopis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phitosia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phitycolax | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Phitymophora | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Phlebocarya | Commelinales | Mabberley (2008) | Haemodoraceae. | ICBN |
| Phlebodium | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Phlebolobium | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Phlebotaenia | Fabales | Mabberley (2008) | Polygalaceae. | ICBN |
| Phlegeria | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Glandulinidae. | ICZN |
| Phlegmatospermum | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Phlegopsis | Passeriformes | Clements (2007) | . | ICZN |
| Phleobum | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Phleocryptes | Passeriformes | Clements (2007) | . | ICZN |
| Phleum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phloeomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Phlogacanthus | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Phlogophilus | Apodiformes | Clements (2007) | . | ICZN |
| Phlogospora | Bivalvulida | Lom & Dyková (2006) | . | ICZN |
| Phlojodicarpus | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Phlomidoschema | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Phlomis | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Phlomobacter | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Phlox | Ericales | Mabberley (2008) | Polemoniaceae. | ICBN |
| Phlyctaenopora | Poecilosclerida | Van Soest & Hajdu (2002) | . | ICZN |
| Phlyctenactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phlyctenanthus | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phlyctidocarpa | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Phlyctimantis | Anura | Vitt & Caldwell (2009) | Hyperoliidae. | ICZN |
| Phoboscincus | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Phoca | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Phocaeicola | Bacteroidales | Al Masalma et al. (2009) | . | ICNB |
| Phocarctos | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Phocoena | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Cetacea. | ICZN |
| Phocoenobacter | Pasteurellales | Garrity et al. (2005) | . | ICNB |
| Phocoenoides | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Cetacea. | ICZN |
| Phodilus | Strigiformes | Clements (2007) | . | ICZN |
| Phodopus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Phoebanthus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phoebastria | Procellariiformes | Clements (2007) | . | ICZN |
| Phoebe | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Phoebetria | Procellariiformes | Clements (2007) | . | ICZN |
| Phoenicanthus | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Phoenicaulis | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Phoeniciloricus | Nanaloricida | Heiner & Kristensen (2009) | . | ICZN |
| Phoenicircus | Passeriformes | Clements (2007) | . | ICZN |
| Phoenicophorium | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Phoenicopterus | Phoenicopteriformes | Clements (2007) | . | ICZN |
| Phoeniculus | Coraciiformes | Clements (2007) | . | ICZN |
| Phoenicurus | Passeriformes | Clements (2007) | . | ICZN |
| Phoenix | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pholia | Passeriformes | Clements (2007) | . | ICZN |
| Pholidobolus | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Pholidocarpus | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pholidornis | Passeriformes | Clements (2007) | . | ICZN |
| Pholidostachys | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pholisma | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pholistoma | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pholiurus | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phoniscus | Chiroptera | Simmons (2005) | . | ICZN |
| Phoradendron | Santalales | Mabberley (2008) | Santalaceae. | ICBN |
| Phorbas | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Phorcysia | Aquificales | Pérez-Rodríguez et al. (2012) | . | ICNB |
| Phoretophrya | Apostomatida | Lynn (2008) | . | ICZN |
| Phoriospongia | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Phormacantha | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Phormidesmis | Oscillatoriales | Turicchia et al. (2009) | . | ICBN |
| Phormidiochaete | Oscillatoriales | Anagnostidis (2001) | . | ICBN |
| Phormidium | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Phormium | Asparagales | Mabberley (2008) | Hemerocallidaceae. | ICBN |
| Phormospyris | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Phormostichoartus | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Photobacterium | Vibrionales | Garrity et al. (2005) | . | ICNB |
| Photorhabdus | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Phoxophrys | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Phractopelta | Arthracanthida | Febvre et al. (2000) | . | ICZN |
| Phragmanthera | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Phragmipedium | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Phragmites | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phragmocarpidium | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Phragmonema | Porphyridiales | Schneider & Wynne (2007) | . | ICBN |
| Phragmorchis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Phragmosporangium | Saprolegniales | Kirk et al. (2008) | Saprolegniaceae. | ICBN |
| Phragmotheca | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Phreatamoeba | Mastigamoebida | Brugerolle & Patterson (2000); Cavalier-Smith et al. (2004) | Later synonym of Mastigamoeba ?. | ICZN |
| Phreatia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Phrodus | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Phryganella | Arcellinida | Meisterfeld (2000) | Phryganellina -- Phryganellidae. | ICZN |
| Phrygilus | Passeriformes | Clements (2007) | . | ICZN |
| Phryma | Lamiales | Mabberley (2008) | Phrymaceae. | ICBN |
| Phrynella | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Phrynium | Zingiberales | Mabberley (2008) | Marantaceae. | ICBN |
| Phrynobatrachus | Anura | Vitt & Caldwell (2009) | Phrynobatrachidae. | ICZN |
| Phrynocephalus | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Phrynoidis | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Phrynomantis | Anura | Vitt & Caldwell (2009) | Microhylidae. | ICZN |
| Phrynomedusa | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Phrynops | Testudinata | Vitt & Caldwell (2009) | Chelidae. | ICZN |
| Phrynopus | Anura | Vitt & Caldwell (2009) | Brachycephalidae. | ICZN |
| Phrynosoma | Squamata | Vitt & Caldwell (2009) | Iguanidae. | ICZN |
| Phthanotrochus | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Phthanotrochidae. | ICZN |
| Phtheirospermum | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Phthirusa | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Phtorophrya | Apostomatida | Lynn (2008) | . | ICZN |
| Phuopsis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phycella | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Phycicoccus | Micrococcales | Lee (2006); Ludwig et al. (2012) | . | ICNB |
| Phycicola | Micrococcales | Lee et al. (2008); Ludwig et al. (2012) | . | ICNB |
| Phycisphaera | Phycisphaerales | Fukunaga et al. (2009) | . | ICNB |
| Phycodrina | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Phycodrys | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Phycogorgia | Alcyonacea | Bayer (1981) | Gorgoniidae. | ICZN |
| Phycolepidozia | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Phycopsis | Halichondrida | Alvarez & Hooper (2002) | . | ICZN |
| Phygelius | Lamiales | Mabberley (2008) | Scrophulariaceae. | ICBN |
| Phyla | Lamiales | Mabberley (2008) | Verbenaceae. | ICBN |
| Phylacium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Phylica | Rosales | Mabberley (2008) | Rhamnaceae. | ICBN |
| Phylidonyris | Passeriformes | Clements (2007) | . | ICZN |
| Phyllacanthus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phyllacineta | Endogenida | Lynn (2008) | . | ICZN |
| Phyllactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phyllagathis | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Phyllangia | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Phyllangium | Gentianales | Mabberley (2008) | Loganiaceae. | ICBN |
| Phyllanoa | Malpighiales | Mabberley (2008) | Violaceae. | ICBN |
| Phyllanthus | Passeriformes | Clements (2007) | . | ICZN |
| Phyllanthus | Malpighiales | Mabberley (2008) | Phyllanthaceae. | ICBN |
| Phyllarthron | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Phyllastrephus | Passeriformes | Clements (2007) | . | ICZN |
| Phyllis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phyllobacterium | Rhizobiales | Garrity et al. (2005) | . | ICNB |
| Phyllobates | Anura | Vitt & Caldwell (2009) | Dendrobatidae. | ICZN |
| Phylloboea | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Phyllobotryon | Malpighiales | Mabberley (2008) | Achariaceae. | ICBN |
| Phyllocara | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Phyllocephalum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phyllochona | Exogemmida | Lynn (2008) | . | ICZN |
| Phyllocladus | Araucariales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Phyllocrater | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phylloctenium | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Phyllocyclus | Gentianales | Mabberley (2008) | Gentianaceae. | ICBN |
| Phyllodactylus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Phylloderma | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Phyllodiscus | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phyllodium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Phyllodoce | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Phyllodon | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Phyllodrepanium | Bryales | Goffinet et al. (2009) | . | ICBN |
| Phyllodytes | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Phyllogonium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Phyllogorgia | Alcyonacea | Bayer (1981) | Gorgoniidae. | ICZN |
| Phyllolais | Passeriformes | Clements (2007) | . | ICZN |
| Phyllomedusa | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Phyllomelia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phyllomyias | Passeriformes | Clements (2007) | . | ICZN |
| Phyllomys | Rodentia | Woods & Kilpatrick (2005) | . | ICZN |
| Phyllonastes | Anura | Vitt & Caldwell (2009) | Brachycephalidae. | ICZN |
| Phyllonoma | Aquifoliales | Mabberley (2008) | Phyllonomaceae. | ICBN |
| Phyllonycteris | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Phyllopezus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Phyllophora | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Phyllopodium | Lamiales | Mabberley (2008) | Scrophulariaceae. | ICBN |
| Phyllops | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Phyllorachis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phyllorhiza | Rhizostomeae | Kramp (1961) | . | ICZN |
| Phyllorhynchus | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Phylloscartes | Passeriformes | Clements (2007) | . | ICZN |
| Phylloscirpus | Poales | Mabberley (2008) | Cyperaceae. | ICBN |
| Phylloscopus | Passeriformes | Clements (2007) | . | ICZN |
| Phyllosma | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Phyllospadix | Alismatales | Mabberley (2008) | Zosteraceae. | ICBN |
| Phyllospongia | Dictyoceratida | Cook & Bergquist (2002) | . | ICZN |
| Phyllostachys | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Phyllostaurus | Arthracanthida | Febvre et al. (2000) | . | ICZN |
| Phyllostegia | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Phyllostemonodaphne | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Phyllostomus | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Phyllostylon | Rosales | Mabberley (2008) | Ulmaceae. | ICBN |
| Phyllota | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Phyllothallia | Fossombroniales | He-Nygrén et al. (2006); Crandall-Stotler et al. (2009) | . | ICBN |
| Phyllothamnus | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Phyllotis | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Phyllotrichum | Chlamydodontida | Lynn (2008) | . | ICZN |
| Phyllotrichum | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Phylloxylon | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Phyllurus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Phylohydrax | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Phymactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phymanthea | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phymanthus | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phymaspermum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Phymatarum | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Phymatidium | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Phymatocarpus | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Phymatoceros | Phymatocerales | Renzaglia et al. (2009) | . | ICBN |
| Phymatodocis | Desmidiales | Gontcharov (2008) | . | ICBN |
| Phymatolithon | Corallinales | Schneider & Wynne (2007) | . | ICBN |
| Phymatopteris | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Phymatosorus | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Phymaturus | Squamata | Vitt & Caldwell (2009) | Iguanidae. | ICZN |
| Phymosia | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Physacanthus | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Physalaemus | Anura | Vitt & Caldwell (2009) | Leiuperidae. | ICZN |
| Physalia | Siphonophorae | Bouillon et al. (2006) | . | ICZN |
| Physalidia | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Bagginidae. | ICZN |
| Physalis | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Physalophrya | Tetrahymenida | Lynn (2008) | . | ICZN |
| Physanter | Peniculida | Lynn (2008) | . | ICZN |
| Physantholejeunea | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Physarella | Physarales | Yamamoto (1998) | . | ICBN |
| Physaria | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Physarina | Physarales | Yamamoto (1998) | . | ICBN |
| Physarum | Physarales | Yamamoto (1998) | . | ICBN |
| Physcomitrella | Funariales | Goffinet et al. (2009) | . | ICBN |
| Physcomitrellopsis | Funariales | Goffinet et al. (2009) | . | ICBN |
| Physcomitrium | Funariales | Goffinet et al. (2009) | . | ICBN |
| Physematium | Spumellaria | Anderson et al. (2000) | . | ICZN |
| Physena | Caryophyllales | Mabberley (2008) | Physenaceae. | ICBN |
| Physeter | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Cetacea. | ICZN |
| Physeterostemon | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Physignathus | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Physocalymma | Myrtales | Mabberley (2008) | Lythraceae. | ICBN |
| Physocalyx | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Physocardamum | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Physocarpus | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Physoceras | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Physochila | Arcellinida | Meisterfeld (2000) | Difflugina -- Nebelidae. | ICZN |
| Physochlaina | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Physochona | Exogemmida | Lynn (2008) | . | ICZN |
| Physogyra | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Physokentia | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Physophora | Siphonophorae | Bouillon et al. (2006) | . | ICZN |
| Physophyllia | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Physoplexis | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Physopsis | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Physoptychis | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Physorhynchus | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Physospermopsis | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Physospermum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Physostegia | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Physostigma | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Physotheca | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Physotrichia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Phytelephas | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Phyteuma | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Phytocoetes | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Phytocrene | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Phytodinium | Phytodiniales | Fensome et al. (1993) | . | ICBN |
| Phytohabitans | Micromonosporales | Inahashi et al. (2010); Ludwig et al. (2012) | Micromonosporaceae . | ICNB |
| Phytolacca | Caryophyllales | Mabberley (2008) | Phytolaccaceae. | ICBN |
| Phytomonas | Trypanosomatida | Moreira et al. (2004) | . | ICZN |
| Phytomonospora | Micromonosporales | Li et al. (2011); Ludwig et al. (2012) | Micromonosporaceae. | ICNB |
| Phytophthora | Peronosporales | Dick (2001); Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Phytopythium | Pythiales | Bala et al. (2010) | Phylogenetically closer to Peronosporales than to Pythium. | ICBN |
| Phytotoma | Passeriformes | Clements (2007) | . | ICZN |
| Phyzelaphryne | Anura | Vitt & Caldwell (2009) | Brachycephalidae. | ICZN |
| Piaranthus | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Piaya | Cuculiformes | Clements (2007) | . | ICZN |
| Pibocella | Flavobacteriales | Nedashkovskaya et al. (2005); Ludwig et al. (2011) | Possibly later synonym of Maribacter. | ICNB |
| Pica | Passeriformes | Clements (2007) | . | ICZN |
| Picardaea | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Picarola | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | Papposphaeraceae. | ICBN |
| Picathartes | Passeriformes | Clements (2007) | . | ICZN |
| Picconia | Lamiales | Mabberley (2008) | Oleaceae. | ICBN |
| Picconiella | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Picea | Pinales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Pichonia | Ericales | Mabberley (2008) | Sapotaceae. | ICBN |
| Pickeringia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Picnomon | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Picochlorum | Chlorellales | Somogyi et al. (2011); Neustupa et al. (2011) | As Nannochloris-like clade. | ICBN |
| Picocystis | | Guillou et al. (2004) | Domain Eucarya - Kingdom Plantae - Phylum Chlorophyta. | ICBN |
| Picoides | Piciformes | Clements (2007) | . | ICZN |
| Picophagus | Picophagales | Cavalier-Smith & Chao (2006) | . | ICBN |
| Picradeniopsis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Picralima | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Picramnia | Picramniales | Mabberley (2008) | Picramniaceae. | ICBN |
| Picrasma | Sapindales | Mabberley (2008) | Simaroubaceae. | ICBN |
| Picrella | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Picria | Lamiales | Mabberley (2008) | Linderniaceae. | ICBN |
| Picris | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Picrodendron | Malpighiales | Mabberley (2008) | Picrodendraceae. | ICBN |
| Picrolemma | Sapindales | Mabberley (2008) | Simaroubaceae. | ICBN |
| Picrophilus | Picrophilales | Garrity et al. (2005) | . | ICNB |
| Picrorhiza | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Picrosia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Picrothamnus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pictetia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pictolejeunea | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pictus | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Piculus | Piciformes | Clements (2007) | . | ICZN |
| Picumnus | Piciformes | Clements (2007) | . | ICZN |
| Picus | Piciformes | Clements (2007) | . | ICZN |
| Pieris | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pierranthus | Lamiales | Mabberley (2008) | Linderniaceae. | ICBN |
| Pierrina | Ericales | Mabberley (2008) | Lecythidaceae. | ICBN |
| Piesika | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Pieterfaurea | Alcyonacea | Verseveldt & Bayer (1988); Williams (2000) | Nidaliidae. | ICZN |
| Piezorhina | Passeriformes | Clements (2007) | . | ICZN |
| Pigafetta | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pigafettoa | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pigmentiphaga | Burkholderiales | Garrity et al. (2005) | . | ICNB |
| Pihiella | Pihiellales | Schneider & Wynne (2007) | . | ICBN |
| Pikea | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Pilalla | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Lagynidae. | ICZN |
| Pilasporangium | Pythiales | Uzuhashi et al. (2010) | . | ICBN |
| Pilea | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Pileanthus | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Pileidinium | | Tamura & Horiguchi (2005) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Dinozoa - Class Dinophyceae. | ICBN |
| Pileocephalus | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pileolus | Euglyphida | Meisterfeld (2000); Özdikmen (2009) | Junior homonym. Substituted by Neopileolus. | ICZN |
| Pileostegia | Cornales | Mabberley (2008) | Hydrangeaceae. | ICBN |
| Pilgerodendron | Cupressales | Farjon (2001); Eckenwalder (2009); Christenhusz et al. (2011) | . | ICBN |
| Pilherodius | Ciconiiformes | Clements (2007) | . | ICZN |
| Pilibacter | Lactobacillales | Higashiguchi et al. (2006) | . | ICNB |
| Pilidiophora | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pilidiostigma | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Pilimelia | Micromonosporales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Piliocolobus | Primates | Groves (2005) | . | ICZN |
| Piliostigma | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pillansia | Asparagales | Mabberley (2008) | Iridaceae. | ICBN |
| Pillotina | Spirochaetales | Garrity et al. (2005) | . | ICNB |
| Piloblephis | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pilocarpus | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pilocosta | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Piloecium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pilophyllum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pilopleura | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pilopogon | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Pilosella | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pilosium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pilosocereus | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pilosporella | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Pilostemon | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pilostyles | Cucurbitales | Mabberley (2008) | Apodanthaceae. | ICBN |
| Pilotrichella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pilotrichidium | Hookeriales | Goffinet et al. (2009) | . | ICBN |
| Pilotrichopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pilotrichum | Hookeriales | Goffinet et al. (2009) | . | ICBN |
| Pilularia | Salviniales | Christenhusz et al. (2011) | . | ICBN |
| Pilulina | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Saccamminidae. | ICZN |
| Pilulinella | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Saccamminidae. | ICZN |
| Pilum | Echinorhynchida | Amin (1985) | . | ICZN |
| Pimelea | Malvales | Mabberley (2008) | Thymelaeaceae. | ICBN |
| Pimelodendron | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pimenta | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Pimentelia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pimpinella | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pinacantha | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pinaciophora | | Patterson et al. (2000); Yabuki et al. (2012) | Domain Eucarya - Phylum Heliozoa - Class Centrohelea, but possibly Nucleariida (Kingdom Fungi - Incertae sedis; Patterson et al., 2000). | ICZN |
| Pinacocoleps | Prorodontida | Foissner et al. (2008) | Colepidae. | ICZN |
| Pinanga | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pinarocorys | Passeriformes | Clements (2007) | . | ICZN |
| Pinaroloxias | Passeriformes | Clements (2007) | . | ICZN |
| Pinaropappus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pinarophyllon | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pinarornis | Passeriformes | Clements (2007) | . | ICZN |
| Pinchatia | Tetrahymenida | Lynn (2008) | . | ICZN |
| Pinckneya | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pinda | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pineda | Malpighiales | Mabberley (2008) | Salicaceae. | ICBN |
| Pinellia | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Pinga | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pingius | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Pinguicula | Lamiales | Mabberley (2008) | Lentibulariaceae. | ICBN |
| Pinguiochrysis | Pinguiochrysidales | Kawachi et al. (2002) | . | ICBN |
| Pinguiococcus | Pinguiochrysidales | Kawachi et al. (2002) | . | ICBN |
| Pinicola | Passeriformes | Clements (2007) | . | ICZN |
| Pinillosia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pinnatella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pinnatiphycus | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Pintoa | Zygophyllales | Mabberley (2008) | Zygophyllaceae. | ICBN |
| Pintospora | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pinus | Pinales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Pinushydra | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pinzona | Dilleniales | Mabberley (2008) | Dilleniaceae. | ICBN |
| Pione | Hadromerida | Rützler (2002) | . | ICZN |
| Pionites | Psittaciformes | Clements (2007) | . | ICZN |
| Pionopsitta | Psittaciformes | Clements (2007) | . | ICZN |
| Pionus | Psittaciformes | Clements (2007) | . | ICZN |
| Piora | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pipa | Anura | Vitt & Caldwell (2009) | Pipidae. | ICZN |
| Pipanacoctomys | Rodentia | Woods & Kilpatrick (2005) | . | ICZN |
| Piper | Piperales | Mabberley (2008) | Piperaceae. | ICBN |
| Pipestela | Halichondrida | Alvarez et al. (2008) | . | ICZN |
| Pipile | Galliformes | Clements (2007) | . | ICZN |
| Pipilo | Passeriformes | Clements (2007) | . | ICZN |
| Pipistrellus | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Pippenalia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pippinia | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Spiroloculinidae. | ICZN |
| Pipra | Passeriformes | Clements (2007) | . | ICZN |
| Pipraeidea | Passeriformes | Clements (2007) | . | ICZN |
| Pipreola | Passeriformes | Clements (2007) | . | ICZN |
| Piprites | Passeriformes | Clements (2007) | . | ICZN |
| Piptadenia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Piptadeniastrum | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Piptadeniopsis | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Piptanthus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Piptatherum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Piptocarpha | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Piptochaetium | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Piptocoma | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Piptolepis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Piptophyllum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Piptoptera | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Piptospatha | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Piptostigma | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Pipturus | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Piqueria | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Piqueriella | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Piranga | Passeriformes | Clements (2007) | . | ICZN |
| Piranhea | Malpighiales | Mabberley (2008) | Picrodendraceae. | ICBN |
| Pireella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pirellula | Planctomycetales | Garrity et al. (2005) | . | ICNB |
| Piresia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Piresiella | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pirinia | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Piriqueta | Malpighiales | Mabberley (2008) | Passifloraceae. | ICBN |
| Pirsonia | Pirsoniales | Cavalier-Smith & Chao (2006) | . | ICZN |
| Pirum | Ichthyophonida | Marshall & Berbee (2011) | . | ICZN |
| Pisanoa | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Piscibacillus | Bacillales | Tanasupawat et al. (2007) | . | ICNB |
| Piscicoccus | Micrococcales | Hamada et al. (2010); Ludwig et al. (2012) | Dermatophilaceae. | ICNB |
| Piscidia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pisciglobus | Lactobacillales | Tanasupawat et al. (2011) | . | ICNB |
| Piscinibacter | Burkholderiales | Stackebrandt et al. (2009) | . | ICNB |
| Piscinoodinium | Gymnodiniales | Fensome et al. (1993); Levy et al. (2007) | The affiliation to Gymnodiniales was not conclusive. | ICBN |
| Piscirickettsia | Thiotrichales | Garrity et al. (2005) | . | ICNB |
| Pisonia | Caryophyllales | Mabberley (2008) | Nyctaginaceae. | ICBN |
| Pisoniella | Caryophyllales | Mabberley (2008) | Nyctaginaceae. | ICBN |
| Pistacia | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pistia | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Pistorinia | Saxifragales | Mabberley (2008) | Crassulaceae. | ICBN |
| Pisum | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pitangus | Passeriformes | Clements (2007) | . | ICZN |
| Pitavia | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pitaviaster | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pitcairnia | Poales | Mabberley (2008) | Bromeliaceae. | ICBN |
| Pithanotomys | Rodentia | McKenna & Bell (1997); Woods & Kilpatrick (2005) | Earlier synonym of Aconaemys. | ICZN |
| Pithecellobium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pithecheir | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pithecheirops | Rodentia | Musser & Carleton (2005) | . | ICZN |
| Pithecia | Primates | McKenna & Bell (1997) | . | ICZN |
| Pithecophaga | Falconiformes | Clements (2007) | . | ICZN |
| Pithecoseris | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pithites | Dysteriida | Lynn (2008) | . | ICZN |
| Pithocarpa | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pithonella | Peridiniales | Fensome et al. (1993) | . | ICBN |
| Pithothorax | Haptorida | Lynn (2008) | . | ICZN |
| Pithys | Passeriformes | Clements (2007) | . | ICZN |
| Pitohui | Passeriformes | Clements (2007) | . | ICZN |
| Pitraea | Lamiales | Mabberley (2008) | Verbenaceae. | ICBN |
| Pitta | Passeriformes | Clements (2007) | . | ICZN |
| Pittasoma | Passeriformes | Clements (2007) | . | ICZN |
| Pittocaulon | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pittoniotis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pittosporopsis | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Pittosporum | Apiales | Mabberley (2008) | Pittosporaceae. | ICBN |
| Pituophis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pityophykos | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pityopsis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pityopus | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pityphyllum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pityranthe | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pityrete | Hexactinosida | Reiswig & Wheeler (2002) | . | ICZN |
| Pityriasis | Passeriformes | Clements (2007) | . | ICZN |
| Pityrodia | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pityrogramma | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Placea | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Placentela | Aplousobranchia | Monniot & Monniot (1972) | Polyclinidae. | ICZN |
| Placentophora | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Placidia | Placidiales | Cavalier-Smith & Chao (2006) | . | ICZN |
| Placinolopha | Homosclerophorida | Muricy & Díaz (2002) | . | ICZN |
| Placocarpa | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Placocista | Euglyphida | Meisterfeld (2000) | . | ICZN |
| Placodiscus | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Placogorgia | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Placojoenia | Cristamonadida | Cepicka et al. (2010) | . | ICZN |
| Placoma | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Placopegma | Lyssacinosida | Tabachnick (2002) | . | ICZN |
| Placophora | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Placopoda | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Placopsilina | Lituolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Placopsilinidae. | ICZN |
| Placopsilinella | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hospitellidae. | ICZN |
| Placorhombus | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | Syracosphaerales ?. | ICBN |
| Placosoma | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Placospermum | Proteales | Mabberley (2008) | Proteaceae. | ICBN |
| Placospherastra | Hadromerida | Van Soest (2009) | . | ICZN |
| Placospongia | Hadromerida | Rützler (2002) | . | ICZN |
| Placotrochides | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Placotrochus | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Placus | Prorodontida | Lynn (2008) | . | ICZN |
| Pladaroxylon | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plagiantha | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Plagianthus | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Plagiobasis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plagiobothrys | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Plagiobryum | Bryales | Pedersen & Hedenäs (2005) | Now checking. | ICBN |
| Plagiocampa | Prorodontida | Lynn (2008) | . | ICZN |
| Plagiocampides | Prorodontida | Lynn (2008) | . | ICZN |
| Plagiocarpus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Plagiochasma | Marchantiales | Crandall-Stotler et al. (2009) | . | ICBN |
| Plagiocheilus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plagiochila | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Plagiochilidium | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Plagiochilion | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Plagiodontia | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Plagiogyria | Cyatheales | Christenhusz et al. (2011) | . | ICBN |
| Plagiolirion | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Plagiolophus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plagiomnium | Bryales | Goffinet et al. (2009) | . | ICBN |
| Plagiopholis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Plagiophrys | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Lagynidae. | ICZN |
| Plagiopogon | Prorodontida | Lynn (2008) | . | ICZN |
| Plagiopteron | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Plagiopus | Bartramiales | Goffinet et al. (2009) | . | ICBN |
| Plagiopyla | Plagiopylida | Lynn (2008) | . | ICZN |
| Plagiopyliella | Philasterida | Lynn (2008) | . | ICZN |
| Plagiopyxis | Arcellinida | Meisterfeld (2000) | Difflugina -- Plagiopyxidae. | ICZN |
| Plagioracelopus | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Plagiorhynchus | Polymorphida | Amin (1985) | . | ICZN |
| Plagioscyphus | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Plagioselmis | Pyrenomonadales | Clay et al. (1999); Deane et al. (2002); Novarino (2003) | . | ICBN |
| Plagiosetum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Plagiosiphon | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Plagiospira | Thigmotrichida | Lynn (2008) | . | ICZN |
| Plagiospora | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Plagiostachys | Zingiberales | Mabberley (2008) | Zingiberaceae. | ICBN |
| Plagiostyles | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Plagiotheciopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Plagiothecium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Plagiotoma | Stichotrichida | Lynn (2008) | . | ICZN |
| Plagius | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plakidium | | Pisera & Lévi (2002) | Domain Eucarya - Kingdom Animalia - Phylum Porifera - Class Demospongiae (lithistids). | ICZN |
| Plakina | Homosclerophorida | Muricy & Díaz (2002) | . | ICZN |
| Plakinastrella | Homosclerophorida | Muricy & Díaz (2002) | . | ICZN |
| Plakortis | Homosclerophorida | Muricy & Díaz (2002) | . | ICZN |
| Plakothira | Cornales | Mabberley (2008) | Loasaceae. | ICBN |
| Planaltoa | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Planchonella | Ericales | Mabberley (2008) | Sapotaceae. | ICBN |
| Planchonia | Ericales | Mabberley (2008) | Lecythidaceae. | ICBN |
| Planctomyces | Planctomycetales | Garrity et al. (2005) | . | ICNB |
| Planctonema | Chlorellales | Darienko et al. (2010) | As Oocystis-clade. | ICBN |
| Planctosphaera | Planctosphaerida | Benito (1982) | . | ICZN |
| Planctostoma | Textulariida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Textulariidae. | ICZN |
| Planea | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Planera | Rosales | Mabberley (2008) | Ulmaceae. | ICBN |
| Planeticovorticella | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Planhoogenraadia | Arcellinida | Meisterfeld (2000) | Difflugina -- Plagiopyxidae. | ICZN |
| Planicoleps | Prorodontida | Lynn (2008) | . | ICZN |
| Planifilum | Bacillales | Hatayama et al. (2005) | . | ICNB |
| Planifolliculina | Heterotrichida | Lynn (2008) | . | ICZN |
| Planigale | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Planilamina | Dysteriida | Lynn (2008) | . | ICZN |
| Planipapillus | Euonychophora | Reid (1996) | Peripatopsidae. | ICZN |
| Planispirillina | Involutinida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992); Sen Gupta (1999) | Planispirillinidae. | ICZN |
| Planispirina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Fischerinidae. | ICZN |
| Planispirinella | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Fischerinidae. | ICZN |
| Planispirinoides | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Spiroloculinidae. | ICZN |
| Planitrichidium | Stichotrichida | Lynn (2008) | nomen nudum. | ICZN |
| Planktocyanocapsa | Synechococcales | Hindak (2002) | . | ICBN |
| Planktolyngbya | Pseudanabaenales | Hoffmann et al. (2005) | . | ICBN |
| Planktonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Planktonetta | Phaeogymnocellida | Takahashi & Anderson (2000) | . | ICZN |
| Planktotalea | Rhodobacterales | Hahnke et al. (2012) | . | ICNB |
| Planktothricoides | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Planktothrix | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Planobacterium | Flavobacteriales | Peng et al. (2009) | . | ICNB |
| Planobispora | Streptosporangiales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Planocarpa | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Planococcus | Bacillales | Garrity et al. (2005) | . | ICNB |
| Planodasys | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Planodes | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Planodinium | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Planodiscorbis | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Rosalinidae. | ICZN |
| Planoglabratella | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Glabratellidae. | ICZN |
| Planogypsina | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Acervulinidae. | ICZN |
| Planolineus | Heteronemertea | Gibson (1995) | . | ICZN |
| Planomicrobium | Bacillales | Garrity et al. (2005) | . | ICNB |
| Planomonas | Ancyromonadida | Cavalier-Smith et al. (2008); Heiss et al. (2010) | Junior synonym of Ancyromonas. | ICZN |
| Planomonospora | Streptosporangiales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Planonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Planonephrys | Pyrenomonadales | Novarino (2003) | Later synonym of Hemiselmis ?. | ICBN |
| Planopolyspora | Micromonosporales | Garrity et al. (2005); Rainey et al. (2012) | Later synonym of Catenuloplanes. | ICNB |
| Planoprotostelium | Protosteliales | Olive (1975) | . | ICBN |
| Planopulvinulina | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Eponididae. | ICZN |
| Planorbulina | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Planorbulinidae. | ICZN |
| Planorbulinella | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Planorbulinidae. | ICZN |
| Planorbulinoides | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Cibicididae. | ICZN |
| Planorbulinopsis | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Planorbulinidae. | ICZN |
| Planosporangium | Micromonosporales | Wiese et al. (2008); Ludwig et al. (2012) | . | ICNB |
| Planotaenium | Zygnematales | Gontcharov & Melkonian (2010) | . | ICBN |
| Planotetraspora | Streptosporangiales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Plantactinospora | Micromonosporales | Qin et al. (2009); Ludwig et al. (2012) | . | ICNB |
| Plantago | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Plantibacter | Micrococcales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Planularia | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Vaginulinidae. | ICZN |
| Planulina | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Planulinidae. | ICZN |
| Planulinoides | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Planulinoididae. | ICZN |
| Plasmodiophora | Plasmodiophorida | Cavalier-Smith (1993); Kirk et al. (2008) | . | ICZN |
| Plasmodium | Haemospororida | Perkins et al. (2000) | . | ICZN |
| Plasmopara | Peronosporales | Dick (2001); Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Plasmoverna | Peronosporales | Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Plasteurhynchium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Plasticicumulans | | Jiang et al. (2011) | Domain Bacteria - Phylum Proteobacteria - Class Gammaproteobacteria. | ICNB |
| Platacanthomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Platalea | Ciconiiformes | Clements (2007) | . | ICZN |
| Platalina | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Platanista | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Cetacea. | ICZN |
| Platanthera | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Platanus | Proteales | Mabberley (2008) | Platanaceae. | ICBN |
| Platea | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Plateilema | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Platella | Amphidiscosida | Tabachnick & Menshenina (2002); Özdikmen (2010) | Junior homonym. Replaced by Tabachnickia. | ICZN |
| Plathymenia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Platicrista | Parachela | Kinchin (1994) | . | ICZN |
| Plationus | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Platoma | Nemastomatales | Schneider & Wynne (2007) | . | ICBN |
| Platonia | Malpighiales | Mabberley (2008) | Guttiferae. | ICBN |
| Platostoma | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Platyamoeba | Vannellida | Rogerson & Patterson (2000); Smirnov et al. (2005); Smirnov et al. (2007) | Later synonym of Vannella. | ICZN |
| Platycapnos | Ranunculales | Mabberley (2008) | Papaveraceae. | ICBN |
| Platycarpha | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Platycarpum | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Platycarya | Fagales | Mabberley (2008) | Juglandaceae. | ICBN |
| Platycaulis | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Platycaulos | Poales | Mabberley (2008) | Restionaceae. | ICBN |
| Platycelyphium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Platycercus | Psittaciformes | Clements (2007) | . | ICZN |
| Platycerium | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Platychilomonas | Kathablepharidida | Patterson et al. (2000); Novarino (2003) | Possibly related to Chilomonas (=Cryptomonas; Cryptomonadales). | ICZN |
| Platychorda | Poales | Mabberley (2008) | Restionaceae. | ICBN |
| Platychrysella | Chromulinales | Kristiansen & Preisig (2001) | Chrysamoebaceae (uniflagellate). | ICBN |
| Platychrysis | Prymnesiales | Jordan et al. (2004) | Prymnesiaceae. | ICBN |
| Platycichla | Passeriformes | Clements (2007) | . | ICZN |
| Platycladus | Cupressales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Platyclinia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Platycodon | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Platycola | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Platycoryne | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Platycrater | Cornales | Mabberley (2008) | Hydrangeaceae. | ICBN |
| Platycyamus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Platydesma | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Platydictya | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Platyemys | Testudinata | Vitt & Caldwell (2009) | Chelidae. | ICZN |
| Platyfolliculina | Heterotrichida | Lynn (2008) | . | ICZN |
| Platygyne | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Platygyra | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Platygyriella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Platygyrium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Platyhypnidium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Platyias | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Platylepis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Platylistrum | Amphidiscosida | Tabachnick & Menshenina (2002) | . | ICZN |
| Platylomella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Platylophus | Passeriformes | Clements (2007) | . | ICZN |
| Platylophus | Oxalidales | Mabberley (2008) | Cunoniaceae. | ICBN |
| Platymantis | Anura | Vitt & Caldwell (2009) | Ceratobatrachidae. | ICZN |
| Platymiscium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Platymitra | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Platymops | Chiroptera | Simmons (2005) | . | ICZN |
| Platynematum | Philasterida | Lynn (2008) | . | ICZN |
| Platyneuron | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Platyophrya | Platyophryida | Lynn (2008); Foissner et al. (2011) | . | ICZN |
| Platyophryides | Platyophryida | Lynn (2008); Foissner et al. (2011) | . | ICZN |
| Platypelis | Anura | Vitt & Caldwell (2009) | Microhylidae. | ICZN |
| Platypholis | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Platyplectrurus | Squamata | Vitt & Caldwell (2009) | Serpentes. Uropeltidae. | ICZN |
| Platypleura | Acanthoecida | Leadbeater & Thomsen (2000); Özdikmen (2009) | Later homonym. Substitutded by Thomsenella. | ICZN |
| Platypodanthera | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Platypodium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Platyproteum | Archigregarinorida | Rueckert & Leander (2009) | Selenidiidae. | ICZN |
| Platypterocarpus | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Platyreta | Aconchulinida | Bass et al. (2009) | . | ICZN |
| Platyrhina | Myliobatiformes | Nelson (2006) | . | ICZN |
| Platyrhinoidis | Myliobatiformes | Nelson (2006) | . | ICZN |
| Platyrhiza | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Platyrinchus | Passeriformes | Clements (2007) | . | ICZN |
| Platyrrhinus | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Platysace | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Platysaurus | Squamata | Vitt & Caldwell (2009) | Cordylidae. | ICZN |
| Platyschkuhria | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Platysepalum | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Platysiphonia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Platysmurus | Passeriformes | Clements (2007) | . | ICZN |
| Platyspermation | Asterales | Mabberley (2008) | Alseuosmiaceae. | ICBN |
| Platysteira | Passeriformes | Clements (2007) | . | ICZN |
| Platystele | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Platystemma | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Platystemon | Ranunculales | Mabberley (2008) | Papaveraceae. | ICBN |
| Platysternon | Testudinata | Vitt & Caldwell (2009) | Platysternidae. | ICZN |
| Platythamnion | Ceramiales | Schneider & Wynne (2007) | Later synonym of Pterothamnion. | ICBN |
| Platytheca | Hibberdiales | Kristiansen & Preisig (2001) | Stylococcaceae. | ICBN |
| Platytheca | Oxalidales | Mabberley (2008) | Elaeocarpaceae. | ICBN |
| Platythelys | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Platytinospora | Ranunculales | Mabberley (2008) | Menispermaceae. | ICBN |
| Platytrochus | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Platyzoanthus | Corallimorpharia | Fautin et al. (2007) | . | ICZN |
| Plaubelia | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Playfairina | Euglyphida | Meisterfeld (2000) | . | ICZN |
| Plazia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plecostachys | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plecotus | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Plectaneia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Plectocomia | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Plectocomiopsis | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Plectonema | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Plectonemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Plectorhyncha | Passeriformes | Clements (2007) | . | ICZN |
| Plectorrhiza | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Plectospira | Saprolegniales | Dick (2001); Kirk et al. (2008) | Leptolegniaceae. | ICBN |
| Plectranthus | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Plectrelminthus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Plectritis | Dipsacales | Mabberley (2008) | Caprifoliaceae. | ICBN |
| Plectrocarpa | Zygophyllales | Mabberley (2008) | Zygophyllaceae. | ICBN |
| Plectrohyla | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Plectroniella | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Plectroninia | Lithonida | Vacelet et al. (2002) | . | ICZN |
| Plectrophenax | Passeriformes | Clements (2007) | . | ICZN |
| Plectrophora | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Plectropterus | Anseriformes | Clements (2007) | . | ICZN |
| Plectrurus | Squamata | Vitt & Caldwell (2009) | Serpentes. Uropeltidae. | ICZN |
| Pleea | Alismatales | Mabberley (2008) | Tofieldiaceae. | ICBN |
| Plegadis | Ciconiiformes | Clements (2007) | . | ICZN |
| Plegmosphaera | Spumellaria | Anderson et al. (2000) | . | ICZN |
| Pleiacanthus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pleioblastus | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pleiocarpa | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pleiocarpidia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pleioceras | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pleiochiton | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pleiocoryne | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pleiocraterium | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pleiogynium | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pleiokirkia | Sapindales | Mabberley (2008) | Kirkiaceae. | ICBN |
| Pleiomeris | Ericales | Mabberley (2008) | Primulaceae. | ICBN |
| Pleione | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pleioneura | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pleiospermium | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pleiospilos | Caryophyllales | Mabberley (2008) | Aizoaceae. | ICBN |
| Pleiostachya | Zingiberales | Mabberley (2008) | Marantaceae. | ICBN |
| Pleiotaxis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pleistophora | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Pleistosporidium | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Plenanemertes | Pelagica | Gibson (1995) | . | ICZN |
| Plenckia | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Pleocarphus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pleochona | Cryptogemmida | Lynn (2008) | . | ICZN |
| Pleocnemia | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pleocola | Arthrotardigrada | Kinchin (1994) | . | ICZN |
| Pleocystidium | Olpidiopsidales | Dick (2001); Kirk et al. (2008) | Olpidiopsidaceae. | ICBN |
| Pleodendron | Canellales | Mabberley (2008) | Canellaceae. | ICBN |
| Pleogyne | Ranunculales | Mabberley (2008) | Menispermaceae. | ICBN |
| Pleomorphomonas | Rhizobiales | Xie, C.-H. & Yokota, A. (2005) | . | ICNB |
| Pleonosporium | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pleonotoma | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Pleopeltis | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pleotrachelus | Rozellopsidales | Dick (2001); Kirk et al. (2008) | Rozellopsidales. | ICBN |
| Pleotrochus | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Pleradenophora | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pleraplysilla | Dictyoceratida | Cook & Bergquist (2002) | . | ICZN |
| Plerogone | Leptomitales | Dick (2001); Kirk et al. (2008) | Leptomitaceae. | ICBN |
| Plerogyra | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Pleroma | | Pisera & Lévi (2002) | Domain Eucarya - Kingdom Animalia - Phylum Porifera - Class Demospongiae (lithistids) Pleromidae. | ICZN |
| Pleromonas | Desmocapsales | Fensome et al. (1993) | . | ICBN |
| Plerotes | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Plesiastrea | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Plesiobatis | Myliobatiformes | Nelson (2006) | . | ICZN |
| Plesiocaryon | Cyrtolophosidida | Lynn (2008) | . | ICZN |
| Plesiocystis | Myxococcales | Garrity et al. (2005) | . | ICNB |
| Plesiodactylactis | Ceriantharia | Tiffon (1987) | . | ICZN |
| Plesiomicrolophus | Squamata | Vitt & Caldwell (2009) | Iguanidae. | ICZN |
| Plesiomonas | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Plesiotricha | Stichotrichida | Lynn (2008) | Later synonym of Kahliella?. | ICZN |
| Plesiotrichopus | Dysteriida | Lynn (2008) | . | ICZN |
| Plesiotrygon | Myliobatiformes | Nelson (2006) | . | ICZN |
| Plestiodon | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Plethadenia | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Plethiandra | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Plethodon | Caudata | Vitt & Caldwell (2009) | Plethodontidae. | ICZN |
| Plethodontohyla | Anura | Vitt & Caldwell (2009) | Microhylidae. | ICZN |
| Pletholax | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Plettkea | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pleuranthodendron | Malpighiales | Mabberley (2008) | Salicaceae. | ICBN |
| Pleuranthodes | Rosales | Mabberley (2008) | Rhamnaceae. | ICBN |
| Pleuranthodium | Zingiberales | Mabberley (2008) | Zingiberaceae. | ICBN |
| Pleurasiga | Acanthoecida | Leadbeater & Thomsen (2000) | . | ICZN |
| Pleuraspis | Arthracanthida | Febvre et al. (2000) | . | ICZN |
| Pleurata | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Pleuretra | Bdelloida | Segers (2002); Segers (2007) | . | ICZN |
| Pleuricospora | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pleuriditrichum | Dicranales | Goffinet et al. (2009) | xPleuriditrichum. | ICBN |
| Pleuridium | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Pleurisanthes | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Pleuroblepharidella | Bonnemaisoniales | Schneider & Wynne (2007) | . | ICBN |
| Pleurobrachia | Cydippida | Harbison & Madin (1982) | . | ICZN |
| Pleurocalyptus | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Pleurocapsa | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Pleurocarpaea | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pleurochaete | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Pleurochilidium | Tetrahymenida | Lynn (2008) | . | ICZN |
| Pleurochloridella | Pleurochloridellales | Kristiansen & Preisig (2001); Bailey et al. (1998) | . | ICBN |
| Pleurochloris | Mischococcales | Ettl (1978) | . | ICBN |
| Pleurochorium | Hexactinosida | Reiswig & Wheeler (2002) | . | ICZN |
| Pleurochrysis | Coccolithales | Edvardsen et al. (2000); Jordan et al. (2004) | Pleurochrysidaceae. | ICBN |
| Pleurocladopsis | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pleurocladula | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pleurocoptes | Pleuronematida | Lynn (2008) | . | ICZN |
| Pleurocoralloides | Alcyonacea | Bayer (1981) | Coralliidae. | ICZN |
| Pleurocoronis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pleurocystis | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pleurodasys | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Pleurodeles | Caudata | Vitt & Caldwell (2009) | Salamandridae. | ICZN |
| Pleurodema | Anura | Vitt & Caldwell (2009) | Leiuperidae. | ICZN |
| Pleurodiscus | Zygnematales | Gontcharov (2008) | . | ICBN |
| Pleurofragma | Prorodontida | Lynn (2008) | . | ICZN |
| Pleurogaster | Mischococcales | Ettl (1978) | . | ICBN |
| Pleurogorgia | Alcyonacea | Bayer (1981) | Chrysogorgiidae. | ICZN |
| Pleuronema | Pleuronematida | Lynn (2008) | . | ICZN |
| Pleuropappus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pleuropetalum | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pleurophascum | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Pleurophora | Myrtales | Mabberley (2008) | Lythraceae. | ICBN |
| Pleurophryodendron | Exogenida | Lynn (2008) | . | ICZN |
| Pleurophrys | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Allogromiidae. | ICZN |
| Pleurophyllum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pleuroplites | Haptorida | Lynn (2008) | . | ICZN |
| Pleuroplitoides | Haptorida | Lynn (2008) | . | ICZN |
| Pleuropogon | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pleuropterantha | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pleurorthotrichum | Orthotrichales | Goffinet et al. (2009) | . | ICBN |
| Pleurosoriopsis | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pleurospermum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pleurostachys | Poales | Mabberley (2008) | Cyperaceae. | ICBN |
| Pleurostichidium | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pleurostima | Pandanales | Mabberley (2008) | Velloziaceae. | ICBN |
| Pleurostomella | Buliminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pleurostomellidae. | ICZN |
| Pleurostomum | Schizopyrenida | Park et al. (2007) | . | ICZN |
| Pleurostylia | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Pleurotaenium | Desmidiales | Gontcharov (2008) | . | ICBN |
| Pleurothallis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pleurothyrium | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Pleurotricha | Sporadotrichida | Lynn (2008) | . | ICZN |
| Pleurotrocha | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Pleurotrochopsis | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Pleurozia | Pleuroziales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pleuroziopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pleurozium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Plexaura | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Plexaurella | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Plexobundleia | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Plica | Squamata | Vitt & Caldwell (2009) | Iguanidae. | ICZN |
| Plicanthus | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Plicatellopsis | Hadromerida | Van Soest (2002) | . | ICZN |
| Plicatoperipatus | Euonychophora | Peck (1975) | Peripatidae. | ICZN |
| Plicatotheca | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Pliciloricus | Nanaloricida | Heiner & Kristensen (2009) | . | ICZN |
| Plicosepalus | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Plinia | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Plinthanthesis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Plinthus | Caryophyllales | Mabberley (2008) | Aizoaceae. | ICBN |
| Pliobothrus | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pliocercus | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Plionemertes | Pelagica | Gibson (1995) | . | ICZN |
| Pliotrema | Pristiophoriformes | Nelson (2006) | . | ICZN |
| Plocama | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Plocamiancora | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Plocamiocolax | Plocamiales | Schneider & Wynne (2007) | . | ICBN |
| Plocamione | Poecilosclerida | Hooper (2002) | . | ICZN |
| Plocamionida | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Plocamium | Plocamiales | Schneider & Wynne (2007) | . | ICBN |
| Plocepasser | Passeriformes | Clements (2007) | . | ICZN |
| Ploceus | Passeriformes | Clements (2007) | . | ICZN |
| Plocoglottis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Plocosperma | Lamiales | Mabberley (2008) | Plocospermataceae. | ICBN |
| Ploeotia | Heteronematales | Leedale (1967); Leedale (2000) | . | ICBN |
| Ploesoma | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Ploiarium | Malpighiales | Mabberley (2008) | Bonnetiaceae. | ICBN |
| Plotnikovina | Textulariida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pseudogaudryinidae. | ICZN |
| Plotocnide | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Plotonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Plowmania | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Plowmanianthus | Commelinales | Mabberley (2008) | Commelinaceae. | ICBN |
| Pluchea | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Plukenetia | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Plumapathes | Antipatharia | Opresko (2001) | . | ICZN |
| Plumarella | Alcyonacea | Bayer (1981) | Primnoidae. | ICZN |
| Plumaria | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Plumariella | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Plumariopsis | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Plumbagella | Caryophyllales | Mabberley (2008) | Plumbaginaceae. | ICBN |
| Plumbago | Caryophyllales | Mabberley (2008) | Plumbaginaceae. | ICBN |
| Plumeria | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Plumigorgia | Alcyonacea | Bayer (1981) | Chrysogorgiidae. | ICZN |
| Plumularia | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Plurella | Phlebobranchia | Kott (1998) | Plurellidae. | ICZN |
| Plutarchia | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pluvialis | Charadriiformes | Clements (2007) | . | ICZN |
| Pluvianellus | Charadriiformes | Clements (2007) | . | ICZN |
| Pluvianthus | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pluvianus | Charadriiformes | Clements (2007) | . | ICZN |
| Pneophyllum | Corallinales | Schneider & Wynne (2007) | . | ICBN |
| Pnoepyga | Passeriformes | Clements (2007) | . | ICZN |
| Poa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Poaephyllum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Poagrostis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Poakatesthia | Peronosporales | Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Pocheina | Acrasida | Kirk et al. (2008) | . | ICZN |
| Pocillopora | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Pocsiella | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Podabacia | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Podachaenium | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Podadenia | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Podager | Caprimulgiformes | Clements (2007) | . | ICZN |
| Podagrostis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Podalyria | Fabales | Mabberley (2008) | LEguminosae. | ICBN |
| Podandra | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Podandrogyne | Brassicales | Mabberley (2008) | Cleomaceae. | ICBN |
| Podangis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Podanthus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Podarcis | Squamata | Vitt & Caldwell (2009) | Lacertidae. | ICZN |
| Podargus | Caprimulgiformes | Clements (2007) | . | ICZN |
| Podica | Gruiformes | Clements (2007) | . | ICZN |
| Podiceps | Podicipediformes | Clements (2007) | . | ICZN |
| Podilymbus | Podicipediformes | Clements (2007) | . | ICZN |
| Podistera | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Podocaelia | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Podocalyx | Malpighiales | Mabberley (2008) | Picrodendraceae. | ICBN |
| Podocapsa | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Podocarpus | Araucariales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Podoces | Passeriformes | Clements (2007) | . | ICZN |
| Podochilus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Podochrysis | | Kristiansen & Preisig (2001) | Domain Eucarya - Kingdom Straminipila - Phylum Ochrophyta. | ICBN |
| Podoclavella | Aplousobranchia | Monniot & Monniot (1972); Kott (1998) | Junior synonym of Clavelina. | ICZN |
| Podocnemis | Testudinata | Vitt & Caldwell (2009) | Podocnemidae. | ICZN |
| Podococcus | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Podocoma | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Podocyathus | Exogenida | Lynn (2008) | . | ICZN |
| Podocytisus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Podogymnura | Eulipotyphla | McKenna & Bell (1997); Murphy et al. (2001) | . | ICZN |
| Podolampas | Peridiniales | Fensome et al. (1993) | . | ICBN |
| Podolasia | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Podolepis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Podolobium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Podolotus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Podomitrium | Fossombroniales | He-Nygrén et al. (2006); Crandall-Stotler et al. (2009) | . | ICBN |
| Podomonas | Apusomonadida | Cavalier-Smith & Chao (2010) | . | ICZN |
| Podomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Podonephelium | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Podophorus | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Podophrya | Exogenida | Lynn (2008) | . | ICZN |
| Podophyllum | Ranunculales | Mabberley (2008) | Berberidaceae. | ICBN |
| Podopterus | Caryophyllales | Mabberley (2008) | Polygonaceae. | ICBN |
| Podorungia | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Podosorus | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Podospongia | Poecilosclerida | Kelly & Samaai (2002) | . | ICZN |
| Podostemum | Malpighiales | Mabberley (2008) | Podostemaceae. | ICBN |
| Podostoma | Dactylopodida | Rogerson & Patterson (2000); Smirnov et al. (2005) | Vexilliferidae. | ICZN |
| Podostyela | Stolidobranchia | Monniot & Monniot (1972) | Styelidae. | ICZN |
| Podotheca | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Podoxymys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Podperaea | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Podranea | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Poecilandra | Malpighiales | Mabberley (2008) | Ochnaceae. | ICBN |
| Poecilanthe | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Poecile | Passeriformes | Clements (2007) | . | ICZN |
| Poecilictis | Carnivora | McKenna & Bell (1997); Wozencraft (2005) | Later synonym of Ictonyx. | ICZN |
| Poecillastra | Astrophorida | Maldonado (2002) | . | ICZN |
| Poecilocalyx | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Poecilodryas | Passeriformes | Clements (2007) | . | ICZN |
| Poecilogale | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Poecilolepis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Poeciloneuron | Malpighiales | Mabberley (2008) | Guttiferae. | ICBN |
| Poecilopholis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Poecilostachys | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Poecilotriccus | Passeriformes | Clements (2007) | . | ICZN |
| Poelagus | Lagomorpha | McKenna & Bell (1997) | . | ICZN |
| Poeltia | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Poeoptera | Passeriformes | Clements (2007) | . | ICZN |
| Poephila | Passeriformes | Clements (2007) | . | ICZN |
| Poeppigia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Poga | Cucurbitales | Mabberley (2008) | Anisophylleaceae. | ICBN |
| Poggea | Malpighiales | Mabberley (2008) | Achariaceae. | ICBN |
| Pogogyne | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pogona | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Pogonachne | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pogonatherum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pogonatum | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Pogonia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pogoniopsis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pogoniulus | Piciformes | Clements (2007) | . | ICZN |
| Pogonochloa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pogonocichla | Passeriformes | Clements (2007) | . | ICZN |
| Pogonolepis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pogonomelomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pogonomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pogononeura | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pogonophora | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pogonopus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pogonotium | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pogonotriccus | Passeriformes | Clements (2007) | . | ICZN |
| Pogostemon | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pohlia | Bryales | Goffinet et al. (2009) | . | ICBN |
| Pohlidium | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pohliella | Malpighiales | Mabberley (2008) | Podostemaceae. | ICBN |
| Poiana | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Poicephalus | Psittaciformes | Clements (2007) | . | ICZN |
| Poikilacanthus | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Poikilogyne | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Poikilonemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Poikilospermum | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Poilanedora | Brassicales | Mabberley (2008) | Excluded from Capparaceae?. | ICBN |
| Poilannammia | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Poincianella | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Poiretia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Poissonia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Poitea | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pojarkovia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polacanthoderes | Cyclorhagida | Sørensen (2008) | . | ICZN |
| Polanisia | Brassicales | Mabberley (2008) | Cleomaceae. | ICBN |
| Polanthion | Rosales | Mabberley (2008) | Rhamnaceae. | ICBN |
| Polarella | Suessiales | Montresor et al. (1999) | . | ICBN |
| Polaribacter | Flavobacteriales | Garrity et al. (2005) | . | ICNB |
| Polaromonas | Burkholderiales | Garrity et al. (2005) | . | ICNB |
| Polaskia | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Polejaevia | Leucosolenida | Borojevic et al. (2002) | . | ICZN |
| Polemaetus | Falconiformes | Clements (2007) | . | ICZN |
| Polemannia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Polemanniopsis | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Polemon | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Polemon | Squamata | Vitt & Caldwell (2009) | Serpentes. Atractaspididae. | ICZN |
| Polemonium | Ericales | Mabberley (2008) | Polemoniaceae. | ICBN |
| Polevansia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Polhillia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Polihierax | Falconiformes | Clements (2007) | . | ICZN |
| Poliocephalus | Podicipediformes | Clements (2007) | . | ICZN |
| Poliolais | Passeriformes | Clements (2007) | . | ICZN |
| Poliomintha | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Poliopogon | Amphidiscosida | Tabachnick & Menshenina (2002) | . | ICZN |
| Poliopsis | Heteronemertea | Gibson (1995) | . | ICZN |
| Polioptila | Passeriformes | Clements (2007) | . | ICZN |
| Poliothyrsis | Malpighiales | Mabberley (2008) | Salicaceae. | ICBN |
| Polioxolmis | Passeriformes | Clements (2007) | . | ICZN |
| Pollexfenia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pollia | Commelinales | Mabberley (2008) | Commelinaceae. | ICBN |
| Pollichia | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Polpoda | Caryophyllales | Mabberley (2008) | Molluginaceae. | ICBN |
| Polskiammina | Trochamminida | Kaminski (2000) | Vialoviinae, Trochamminacea. | ICZN |
| Polyacanthorhynchus | Polyacanthorhynchida | Amin (1985); Amin (1987) | Polyacanthorhynchidae. | ICZN |
| Polyachyrus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polyalthia | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Polyandrocarpa | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Styelidae. | ICZN |
| Polyangium | Myxococcales | Garrity et al. (2005) | . | ICNB |
| Polyanthina | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polyarrhena | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polyarthra | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Polyaster | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Polyboroides | Falconiformes | Clements (2007) | . | ICZN |
| Polybotrya | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Polybrachiorhynchus | Heteronemertea | Gibson (1995) | . | ICZN |
| Polycalymma | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polycanthus | Acoela | Hooge (2003) | . | ICZN |
| Polycardia | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Polycarena | Lamiales | Mabberley (2008) | Scrophulariaceae. | ICBN |
| Polycarpa | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Styelidae. | ICZN |
| Polycarpaea | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Polycarpon | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Polycephalium | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Polyceratocarpus | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Polychaos | Euamoebida | Rogerson & Patterson (2000); Smirnov et al. (2005) | . | ICZN |
| Polychlamydum | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Polychoerus | Acoela | Dörjes (1968); Hooge & Tyler (2005) | . | ICZN |
| Polychromophilus | Haemospororida | Perkins et al. (2000) | . | ICZN |
| Polychrus | Squamata | Vitt & Caldwell (2009) | Iguanidae. | ICZN |
| Polychrysum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polycitor | Aplousobranchia | Monniot & Monniot (1972); Monniot (2001) | Polycitoridae. | ICZN |
| Polycitorella | Aplousobranchia | Monniot & Monniot (1972); Kott (1998) | Junior synonym of Eucoelium. | ICZN |
| Polyclathra | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Polyclinella | Aplousobranchia | Monniot & Monniot (1972); Monniot (2001) | Polyclinidae. | ICZN |
| Polyclinum | Aplousobranchia | Monniot & Monniot (1972); Monniot (2001) | Polyclinidae. | ICZN |
| Polyclita | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Polycnemum | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Polycoelia | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Polycoryne | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Polycosta | Macropodiniida | Lynn (2008) | . | ICZN |
| Polycrater | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | Alisphaeraceae ?. | ICBN |
| Polyctenium | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Polycyathus | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Polycycla | Mobilida | Lynn (2008) | . | ICZN |
| Polycycnis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Polydendrorhynchus | Heteronemertea | Gibson (1995); Kajihara et al. (2008) | Junior synonym of and replacement name for Dendrorhynchus. | ICZN |
| Polydendrorhynchus | Heteronemertea | Kajihara et al. (2008) | . | ICZN |
| Polydiniella | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Polydispyrenia | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Polydistoma | Aplousobranchia | Kott (1998) | Holozoidae. | ICZN |
| Polyedriella | Mischococcales | Ettl (1978) | . | ICBN |
| Polyerata | Apodiformes | Clements (2007) | . | ICZN |
| Polyfibula | Acanthoecida | Leadbeater & Thomsen (2000) | . | ICZN |
| Polygala | Fabales | Mabberley (2008) | Polygalaceae. | ICBN |
| Polygonanthus | Cucurbitales | Mabberley (2008) | Anisophylleaceae. | ICBN |
| Polygonatum | Asparagales | Mabberley (2008) | Asparagaceae. | ICBN |
| Polygonella | Caryophyllales | Mabberley (2008) | Polygonaceae. | ICBN |
| Polygoniochloris | Mischococcales | Ettl (1978) | . | ICBN |
| Polygonum | Caryophyllales | Mabberley (2008) | Polygonaceae. | ICBN |
| Polyides | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Polykrikos | Gymnodiniales | Fensome et al. (1993) | . | ICBN |
| Polykyrtos | Chloramoebales | Ettl (1978) | . | ICBN |
| Polylepidomonas | Paraphysomonadales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Paraphysomonadaceae. | ICBN |
| Polylepis | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Polylophium | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Polylychnis | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Polymastia | Hadromerida | Boury-Esnault (2002) | . | ICZN |
| Polymastigoides | Cristamonadida | Cepicka et al. (2010) | . | ICZN |
| Polymastix | Oxymonadida | Brugerolle & Lee (2000) | . | ICZN |
| Polymeria | Solanales | Mabberley (2008) | Convolvulaceae. | ICBN |
| Polymerodon | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Polymerurus | Chaetonotida | Balsamo et al. (2009) | . | ICZN |
| Polymita | Caryophyllales | Mabberley (2008) | Aizoaceae. | ICBN |
| Polymnia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polymorphella | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Polymorphina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Polymorphinidae. | ICZN |
| Polymorphospora | Micromonosporales | Tamura et al. (2006); Ludwig et al. (2012) | . | ICNB |
| Polymorphus | Polymorphida | Amin (1985) | . | ICZN |
| Polymyces | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Polymyxa | Plasmodiophorida | Cavalier-Smith (1993); Kirk et al. (2008) | . | ICZN |
| Polyneura | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Polyneurella | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Polyneuropsis | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Polynucleobacter | Burkholderiales | Garrity et al. (2005); Görtz & Schmidt (2005) | . | ICNB |
| Polyoctacnemus | Phlebobranchia | Monniot & Monniot (1972) | Octacnemidae. | ICZN |
| Polyoeca | Acanthoecida | Leadbeater & Thomsen (2000) | . | ICZN |
| Polyonymus | Apodiformes | Clements (2007) | . | ICZN |
| Polyopes | Cryptonemiales | Silva (2002); Schneider & Wynne (2007) | . | ICBN |
| Polyorchis | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Polyosma | Escalloniales | Mabberley (2008) | Escalloniaceae. | ICBN |
| Polyotidium | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Polypedates | Anura | Vitt & Caldwell (2009) | Rhacophoridae. | ICZN |
| Polyphlebium | Hymenophyllales | Christenhusz et al. (2011) | . | ICBN |
| Polyphyllia | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Polyplacocystis | Acanthocystida | Mikrjukov et al. (2000); Cavalier-Smith & von der Heyden (2007); Yabuki et al. (2012) | Raphidiophryidae. | ICZN |
| Polyplastron | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Polyplectron | Galliformes | Clements (2007) | . | ICZN |
| Polypleurella | Malpighiales | Mabberley (2008) | Podostemaceae. | ICBN |
| Polypleurum | Malpighiales | Mabberley (2008) | Podostemaceae. | ICBN |
| Polyplumaria | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Polypodiopteris | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Polypodium | | Raikova (1988); Bouillon et al. (2006); Evans et al. (2008); Evans et al. (2009) | Domain Eucarya - Kingdom Animalia - Phylum Cnidaria - Class Polypodiozoa. | ICZN |
| Polypodium | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Polypodochrysis | Pinguiochrysidales | Kawachi et al. (2002) | . | ICBN |
| Polypogon | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Polyporandra | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Polypremum | Lamiales | Mabberley (2008) | Tetrachondraceae. | ICBN |
| Polypsecadium | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Polypyramis | Phaeocalpida | Takahashi & Anderson (2000) | . | ICZN |
| Polyrhabda | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Polyrhabdina | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Polyrhiza | Rhizostomeae | Kramp (1961) | . | ICZN |
| Polysaccammina | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Polysaccamminidae. | ICZN |
| Polyschista | Reptantia | Gibson (1995) | . | ICZN |
| Polyscias | Apiales | Mabberley (2008) | Araliaceae. | ICBN |
| Polysegmentina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Polysiphonia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Polyspatha | Commelinales | Mabberley (2008) | Commelinaceae. | ICBN |
| Polysphaeria | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Polysphondylium | Dictyosteliales | Hagiwara (1989) | . | ICBN |
| Polyspira | Apostomatida | Lynn (2008) | . | ICZN |
| Polysporella | Eucoccidiorida | Perkins et al. (2000) | . | ICZN |
| Polysporoplasma | Bivalvulida | Lom & Dyková (2006) | . | ICZN |
| Polystachya | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Polystemma | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Polystemonanthus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Polystichopsis | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Polystichum | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Polysticta | Anseriformes | Clements (2007) | . | ICZN |
| Polystictus | Passeriformes | Clements (2007) | . | ICZN |
| Polystomammina | Trochamminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Trochamminidae. | ICZN |
| Polystrata | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Polysyncraton | Aplousobranchia | Monniot & Monniot (1972); Monniot (2001) | Didemnidae. | ICZN |
| Polytaenia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Polytaenium | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Polytaxis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Polytelis | Psittaciformes | Clements (2007) | . | ICZN |
| Polytepalum | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Polytmus | Apodiformes | Clements (2007) | . | ICZN |
| Polytoca | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Polytrias | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Polytrichadelphus | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Polytrichastrum | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Polytrichum | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Polyura | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Polyzoa | Stolidobranchia | Monniot & Monniot (1972) | Styelidae. | ICZN |
| Polyzonia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Polyzygus | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pomaderris | Rosales | Mabberley (2008) | Rhamnaceae. | ICBN |
| Pomania | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pomarea | Passeriformes | Clements (2007) | . | ICZN |
| Pomaria | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pomatocalpa | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pomatodinium | Noctilucales | Fensome et al. (1993) | . | ICBN |
| Pomatorhinus | Passeriformes | Clements (2007) | . | ICZN |
| Pomatostomus | Passeriformes | Clements (2007) | . | ICZN |
| Pomax | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pombalia | Malpighiales | Mabberley (2008) | Violaceae. | ICBN |
| Pometia | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Pommereschea | Zingiberales | Mabberley (2008) | Zingiberaceae. | ICBN |
| Pommereulla | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pomoriella | Arcellinida | Meisterfeld (2000) | Difflugina -- Lesquereusiidae. | ICZN |
| Pompholyx | Flosculariaceae | Segers (2002); Segers (2007) | . | ICZN |
| Pompholyxia | | Lynn (2008) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora. | ICZN |
| Pompholyxophrys | Nucleariida | Patterson et al. (2000) | . | ICZN |
| Pomphorhynchus | Echinorhynchida | Amin (1985) | . | ICZN |
| Ponapea | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Ponera | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Ponerorchis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pongamiopsis | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pongo | Primates | McKenna & Bell (1997) | . | ICZN |
| Pontechium | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pontederia | Commelinales | Mabberley (2008) | Pontederiaceae. | ICBN |
| Pontesia | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Ponthieva | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pontibaca | Rhodobacterales | Kim et al. (2010) | . | ICNB |
| Pontibacillus | Bacillales | Lim et al. (2005) | . | ICNB |
| Pontibacter | Cytophagales | Nedashkovskaya et al. (2005); Ludwig et al. (2011) | . | ICNB |
| Ponticaulis | | Williams et al. (2007); Kang & Lee (2009) | Domain Bacteria - Phylum Proteobacteria - Class Alphaproteobacteria. Hyphomonadaceae. | ICNB |
| Ponticoccus | Rhodobacterales | Hwang & Cho (2008) | . | ICNB |
| Pontigulasia | Arcellinida | Meisterfeld (2000) | Difflugina -- Difflugiidae. | ICZN |
| Pontirhabdus | Flavobacteriales | Yi et al. (2011) | . | ICNB |
| Pontisma | | Dick (2001); Kirk et al. (2008) | Domain Eucarya - Kingdom Straminipila - Phylum Oomycota. Pontismataceae. | ICBN |
| Pontolineus | Heteronemertea | Gibson (1995) | . | ICZN |
| Pontomyxa | | Bass et al. (2009) | Domain Eucarya - Rhizaria - incertae sedis - Family Rhizoplasmidae. | ICZN |
| Pontoporia | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Cetacea. | ICZN |
| Pontosphaera | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | Pontosphaeraceae. | ICBN |
| Ponturostyla | Sporadotrichida | Lynn (2008) | . | ICZN |
| Pooecetes | Passeriformes | Clements (2007) | . | ICZN |
| Poospiza | Passeriformes | Clements (2007) | . | ICZN |
| Popeia | Squamata | Vitt & Caldwell (2009) | Serpentes. Viperidae. | ICZN |
| Popelairia | Apodiformes | Clements (2007) | . | ICZN |
| Popoviolimon | Caryophyllales | Mabberley (2008) | Plumbaginaceae. | ICBN |
| Popowia | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Populina | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Populus | Malpighiales | Mabberley (2008) | Salicaceae. | ICBN |
| Poralia | Semaeostomeae | Kramp (1961) | . | ICZN |
| Porana | Solanales | Mabberley (2008) | Convolvulaceae. | ICBN |
| Poranopsis | Solanales | Mabberley (2008) | Convolvulaceae. | ICBN |
| Poranthera | Malpighiales | Mabberley (2008) | Phyllanthaceae. | ICBN |
| Poraqueiba | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Porcelia | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Porella | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Poricalyptra | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | former Calyptrosphaeraceae. | ICBN |
| Poritectolithus | Coccolithales | Jordan et al. (2004); Edvardsen & Medlin (2007) | former Calyptrosphaeraceae. | ICBN |
| Poritella | | Pisera & Lévi (2002) | Domain Eucarya - Kingdom Animalia - Phylum Porifera - Class Demospongiae (lithistids); Probably synonymous to Leiodermatium. | ICZN |
| Porites | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Poritextularia | Textulariida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Textulariidae. | ICZN |
| Poritipora | Scleractinia | Veron (2000) | . | ICZN |
| Porlieria | Zygophyllales | Mabberley (2008) | Zygophyllaceae. | ICBN |
| Porochrysis | Ochromonadales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Dinobryaceae (uniflagellate). | ICBN |
| Porocystis | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Poroderma | Carcharhiniformes | Nelson (2006) | . | ICZN |
| Poroeponides | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Eponididae. | ICZN |
| Porolabium | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Poromera | Squamata | Vitt & Caldwell (2009) | Lacertidae. | ICZN |
| Porophyllum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Porosia | Arcellinida | Meisterfeld (2000) | Difflugina -- Nebelidae. | ICZN |
| Porospathis | Phaeocalpida | Takahashi & Anderson (2000) | . | ICZN |
| Porospora | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Porostylon | Hibberdiales | Kristiansen & Preisig (2001) | Stylococcaceae. | ICBN |
| Porotrichodendron | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Porotrichopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Porotrichum | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Porpax | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Porphyra | Bangiales | Schneider & Wynne (2007) | . | ICBN |
| Porphyria | Verongida | Bergquist & Cook (2002) | . | ICZN |
| Porphyridium | Porphyridiales | Schneider & Wynne (2007) | . | ICBN |
| Porphyrio | Gruiformes | Clements (2007) | . | ICZN |
| Porphyrobacter | Sphingomonadales | Garrity et al. (2005) | . | ICNB |
| Porphyrodesme | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Porphyroglossum | Gelidiales | Schneider & Wynne (2007) | . | ICBN |
| Porphyroglottis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Porphyrolaema | Passeriformes | Clements (2007) | . | ICZN |
| Porphyromonas | Bacteroidales | Garrity et al. (2005) | . | ICNB |
| Porphyropsis | Erythropeltidales | Schneider & Wynne (2007) | . | ICBN |
| Porphyrosiphon | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Porphyrospiza | Passeriformes | Clements (2007) | . | ICZN |
| Porphyrostachys | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Porphyrostemma | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Porphyrostromium | Erythropeltidales | Schneider & Wynne (2007); Wynne & Schneider (2010) | Later synonym of Smithora. | ICBN |
| Porpita | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Porpostoma | Philasterida | Lynn (2008) | Later synonym of Helicostoma?. | ICZN |
| Porroglossum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Porrorchis | Polymorphida | Amin (1985) | . | ICZN |
| Porrorhachis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Portatrochammina | Trochamminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Trochamminidae. | ICZN |
| Portea | Poales | Mabberley (2008) | Bromeliaceae. | ICBN |
| Portenschlagiella | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Porterandia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Porterella | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Porteresia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Porthidium | Squamata | Vitt & Caldwell (2009) | Serpentes. Viperidae. | ICZN |
| Porticoccus | | Oh et al. (2010) | Domain Bacteria - Phylum Proteobacteria - Class Gammaproteobacteria. | ICNB |
| Portieria | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Portlandia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Portulaca | Caryophyllales | Mabberley (2008) | Portulacaceae. | ICBN |
| Portulacaria | Caryophyllales | Mabberley (2008) | Didiereaceae. | ICBN |
| Porzana | Gruiformes | Clements (2007) | . | ICZN |
| Posadaea | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Poseidon | Heteronemertea | Kajihara et al. (2008) | . | ICZN |
| Poseidonemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Poseidonocella | Rhodobacterales | Romanenko et al. (2012) | . | ICNB |
| Posidonia | Alismatales | Mabberley (2008) | Posidoniaceae. | ICBN |
| Poskea | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Posoqueria | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Postaphanostoma | Acoela | Dörjes (1968); Faubel & Noreña (2001); Hooge & Tyler (2005) | . | ICZN |
| Postechiella | Flavobacteriales | Lee et al. (2012) | . | ICNB |
| Postgaardi | Postgaardida | Cavalier-Smith (2003) | . | ICZN |
| Posticopora | Acoela | Kozloff (2000) | Under confirmation. | ICZN |
| Postiella | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Postmecynostomum | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Potalia | Gentianales | Mabberley (2008) | Gentianaceae. | ICBN |
| Potameia | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Potamites | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Potamium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Potamochoerus | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Artiodactyla. | ICZN |
| Potamogale | Afrosoricida | McKenna & Bell (1997); Stanhope et al. (1998) | Tenrecidae. | ICZN |
| Potamogeton | Alismatales | Mabberley (2008) | Potamogetonaceae. | ICBN |
| Potamolepis | Haplosclerida | Manconi & Pronzato (2002) | . | ICZN |
| Potamonemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Potamophila | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Potamophloios | Haplosclerida | Manconi & Pronzato (2002) | . | ICZN |
| Potamostoma | Eumonostilifera | Chernyshev (2005); Kajihara et al. (2008) | Sacconemertidae. | ICZN |
| Potamotrygon | Myliobatiformes | Nelson (2006) | . | ICZN |
| Potaninia | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Potarophytum | Poales | Mabberley (2008) | Rapateaceae. | ICBN |
| Potentilla | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Poteranthera | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Poterioochromonas | Ochromonadales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Dinobryaceae (biflagellate). | ICBN |
| Poteriospumella | Ochromonadales | Findenig et al. (2010) | . | ICBN |
| Pothoidium | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Pothos | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Potomacus | Philasterida | Lynn (2008) | . | ICZN |
| Potomotyphlus | Gymnophiona | Vitt & Caldwell (2009) | Typhlonectidae. | ICZN |
| Potorous | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Potos | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Potoxylon | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Pottia | Pottiales | Werner et al. (2004) | . | ICBN |
| Pottingeria | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Pottiopsis | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Pottsia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pottsiocles | Endogenida | Lynn (2008) | . | ICZN |
| Pouchetia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Poulsenia | Rosales | Mabberley (2008) | Moraceae. | ICBN |
| Poupartia | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pourouma | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Pourriotia | Ploima | De Smet (2003); Segers (2007) | Notommatidae. | ICZN |
| Pourtalocyathus | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Pourtalosmilia | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Pouteria | Ericales | Mabberley (2008) | Sapotaceae. | ICBN |
| Pouzolzia | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Povedadaphne | Laurales | Mabberley (2008) | Lauraceae. | ICBN |
| Powellia | Hypnodendrales | Goffinet et al. (2009) | . | ICBN |
| Poyntonia | Anura | Vitt & Caldwell (2009) | Pyxicephalidae. | ICZN |
| Poyntonophrynus | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Pozoa | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pozziella | Poecilosclerida | Hajdu (2002) | . | ICZN |
| Pradosia | Ericales | Mabberley (2008) | Sapotaceae. | ICBN |
| Praealbonemertes | Heteronemertea | Gibson (1995) | . | ICZN |
| Praeanaperus | Acoela | Faubel & Noreña (2001) | . | ICZN |
| Praeaphanostoma | Acoela | Dörjes (1968); Faubel & Noreña (2001); Hooge & Tyler (2005) | . | ICZN |
| Praecereus | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Praecitrullus | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Praeconvoluta | Acoela | Dörjes (1968); Faubel & Noreña (2001); Hooge & Tyler (2005) | . | ICZN |
| Praecoxanthus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Praeglobobulimina | Buliminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Buliminidae. | ICZN |
| Praesagittifera | Acoela | Kostenko & Mamkaev (1990) | Under confirmation. | ICZN |
| Praescutata | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Praethecacineta | Exogenida | Lynn (2008) | . | ICZN |
| Praeukrohnia | Phragmophora | Kasatkina & Stolyarova (2006) | Eukrohniidae. | ICZN |
| Pragia | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Prainea | Rosales | Mabberley (2008) | Moraceae. | ICBN |
| Pranceacanthus | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Prangos | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Praomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Praravinia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Prasanthus | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Prasinocladus | Chlorodendrales | Massjuk (2006) | . | ICBN |
| Prasinococcus | | Moestrup (2000); Guillou et al. (2004) | Domain Eucarya - Kingdom Plantae - Phylum Chlorophyta. "Prasinococcales". | ICBN |
| Prasinoderma | | Guillou et al. (2004) | Domain Eucarya - Kingdom Plantae - Phylum Chlorophyta. "Prasinococcales". | ICBN |
| Prasinohaema | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Prasiococcus | Prasiolales | Rindi et al. (2007) | . | ICBN |
| Prasiola | Prasiolales | Rindi et al. (2007) | . | ICBN |
| Prasiolopsis | Prasiolales | Rindi et al. (2007) | . | ICBN |
| Prasium | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Praslinia | Gymnophiona | Vitt & Caldwell (2009) | "Caeciliidae". | ICZN |
| Prasophyllum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Prauserella | Pseudonocardiales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Pravinaria | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Praxeliopsis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Praxelis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Praya | Siphonophorae | Bouillon et al. (2006) | . | ICZN |
| Prayola | Siphonophorae | Bouillon et al. (2006) | . | ICZN |
| Preactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Predaea | Nemastomatales | Schneider & Wynne (2007) | . | ICBN |
| Predurostyla | Heterotrichida | Lynn (2008) | . | ICZN |
| Preissia | Marchantiales | Crandall-Stotler et al. (2009) | . | ICBN |
| Premna | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Premnoplex | Passeriformes | Clements (2007) | . | ICZN |
| Premnornis | Passeriformes | Clements (2007) | . | ICZN |
| Premocyathus | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Prenanthella | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Prenanthenia | Asterales | Mabberley (2008) | xPrenanthenia. Prenanthes x Sventenia (later synonym of Sonchus) hybrids. Compositae. | ICBN |
| Prenanthes | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Preperidinium | Peridiniales | Fensome et al. (1993) | . | ICBN |
| Prepodesma | Caryophyllales | Mabberley (2008) | Aizoaceae. | ICBN |
| Preptychostomum | Thigmotrichida | Lynn (2008) | . | ICZN |
| Prepusa | Gentianales | Mabberley (2008) | Gentianaceae. | ICBN |
| Presbytis | Primates | McKenna & Bell (1997) | . | ICZN |
| Prescottia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Prescottiella | Desmidiales | Bicudo (1976); Gontcharov (2008) | . | ICBN |
| Presliophytum | Cornales | Mabberley (2008) | Loasaceae. | ICBN |
| Prestelia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Prestoea | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Prestonia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Preussiella | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Preussiodora | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Prevotella | Bacteroidales | Garrity et al. (2005) | . | ICNB |
| Priapulopsis | Priapulomorpha | Adrianov & Malakhov (1996) | . | ICZN |
| Priapulus | Priapulomorpha | Adrianov & Malakhov (1996) | . | ICZN |
| Pricia | Flavobacteriales | Yu et al. (2012) | . | ICNB |
| Primnoa | Alcyonacea | Bayer (1981) | Primnoidae. | ICZN |
| Primnoella | Alcyonacea | Bayer (1981) | Primnoidae. | ICZN |
| Primnoisis | Alcyonacea | Bayer (1981) | Isididae. | ICZN |
| Primolius | Psittaciformes | Clements (2007) | . | ICZN |
| Primorskyibacter | Rhodobacterales | Romanenko et al. (2011) | . | ICNB |
| Primula | Ericales | Mabberley (2008) | Primulaceae. | ICBN |
| Primulina | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Principina | Poales | Mabberley (2008) | Cyperaceae. | ICBN |
| Pringlea | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pringleella | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Prinia | Passeriformes | Clements (2007) | . | ICZN |
| Prinsepia | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Printzia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Priodontes | Xenarthra | McKenna & Bell (1997) | . | ICZN |
| Priogymnanthus | Lamiales | Mabberley (2008) | Oleaceae. | ICBN |
| Prionace | Carcharhiniformes | Nelson (2006) | . | ICZN |
| Prionailurus | Carnivora | Wozencraft (2005) | . | ICZN |
| Prionanthium | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Prionitis | Cryptonemiales | Silva (2002); Schneider & Wynne (2007) | Later synonym of Grateloupia. | ICBN |
| Prioniturus | Psittaciformes | Clements (2007) | . | ICZN |
| Prionium | Poales | Mabberley (2008) | Thurniaceae. | ICBN |
| Prionochilus | Passeriformes | Clements (2007) | . | ICZN |
| Prionodon | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Prionodon | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Prionodura | Passeriformes | Clements (2007) | . | ICZN |
| Prionolejeunea | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Prionomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Prionops | Passeriformes | Clements (2007) | . | ICZN |
| Prionosciadium | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Prionostemma | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Prionotes | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Prioria | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Priotelus | Trogoniformes | Clements (2007) | . | ICZN |
| Prismatella | Mischococcales | Ettl (1978) | . | ICBN |
| Prismatocarpus | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Prismatomeris | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Prismatomorphia | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Vaginulinidae. | ICZN |
| Prismatospora | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pristacantha | Arthracanthida | Febvre et al. (2000) | . | ICZN |
| Pristidactylus | Squamata | Vitt & Caldwell (2009) | Iguanidae. | ICZN |
| Pristimantis | Anura | Vitt & Caldwell (2009) | Brachycephalidae. | ICZN |
| Pristimera | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Pristinosceptrella | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ellipsolagenidae. | ICZN |
| Pristiophorus | Pristiophoriformes | Nelson (2006) | . | ICZN |
| Pristis | Pristiformes | Nelson (2006) | . | ICZN |
| Pristurus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Pritchardia | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pritchardiopsis | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Priva | Lamiales | Mabberley (2008) | Verbenaceae. | ICBN |
| Proablepharus | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Proagnesia | Phlebobranchia | Monniot (2001) | Agneziidae. | ICZN |
| Proales | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Proalides | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Proalinopsis | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Proamphorella | Tintinnida | Lynn (2008) | . | ICZN |
| Proaphanostoma | Acoela | Faubel & Noreña (2001); Hooge & Tyler (2005) | . | ICZN |
| Proarmaueria | Pelagica | Gibson (1995) | . | ICZN |
| Proarmaueriella | Pelagica | Gibson (1995) | . | ICZN |
| Proatheris | Squamata | Vitt & Caldwell (2009) | Serpentes. Viperidae. | ICZN |
| Proaulax | | Fensome et al. (1993) | Domain Eucarya - Phylum Dinozoa - Superclass Dinokaryota. | ICBN |
| Probalaenanemertes | Pelagica | Gibson (1995) | . | ICZN |
| Problognathia | Bursovaginoidea | Sørensen (2002) | . | ICZN |
| Proboscidactyla | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Proboscidea | Lamiales | Mabberley (2008) | Martyniaceae. | ICBN |
| Proboscidium | Haptorida | Lynn (2008) | . | ICZN |
| Probosciger | Psittaciformes | Clements (2007) | . | ICZN |
| Proboveria | Thigmotrichida | Lynn (2008) | . | ICZN |
| Probreviceps | Anura | Vitt & Caldwell (2009) | Brevicipitidae. | ICZN |
| Procabacter | Procabacteriales | Garrity et al. (2005) | . | ICNB |
| Procapra | Artiodactyla | Grubb (2005) | . | ICZN |
| Procavia | Hyracoidea | McKenna & Bell (1997) | . | ICZN |
| Procellaria | Procellariiformes | Clements (2007) | . | ICZN |
| Procellosaurinus | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Procelsterna | Charadriiformes | Clements (2007) | . | ICZN |
| Procephalothrix | Palaeonemertea | Gibson (1995); Kajihara et al. (2008) | Junior synonym of Cephalothrix. | ICZN |
| Proceratophrys | Anura | Vitt & Caldwell (2009) | Cycloramphidae. | ICZN |
| Procerolagena | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Lagenidae. | ICZN |
| Prochlorococcus | Synechococcales | Hoffmann et al. (2005) | . | ICBN |
| Prochloron | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Prochlorothrix | Pseudanabaenales | Hoffmann et al. (2005) | . | ICBN |
| Prockia | Malpighiales | Mabberley (2008) | Salicaceae. | ICBN |
| Prockiopsis | Malpighiales | Mabberley (2008) | Achariaceae. | ICBN |
| Proclausilocola | Astomatida | Lynn (2008) | . | ICZN |
| Proclavarctus | Arthrotardigrada | Kinchin (1994) | . | ICZN |
| Procnias | Passeriformes | Clements (2007) | . | ICZN |
| Procolobus | Primates | Groves (2005) | . | ICZN |
| Procondylostoma | Heterotrichida | Lynn (2008) | . | ICZN |
| Proconvoluta | Acoela | Dörjes (1968); Faubel & Noreña (2001); Hooge & Tyler (2005) | . | ICZN |
| Procris | Rosales | Mabberley (2008) | Urticaceae. | ICBN |
| Procryptobia | Parabodonida | Moreira et al. (2004) | . | ICZN |
| Proctoporus | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Procyon | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Prodiscocephalus | Euplotida | Lynn (2008) | . | ICZN |
| Prodiscophrya | Evaginogenida | Lynn (2008) | . | ICZN |
| Prodotiscus | Piciformes | Clements (2007) | . | ICZN |
| Proechimys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Proechiniscus | Echiniscoidea | Kinchin (1994) | . | ICZN |
| Proecus | Tintinnida | Lynn (2008) | . | ICZN |
| Proedromys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Proemassilina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Profelis | Carnivora | Wozencraft (2005) | . | ICZN |
| Profilicollis | Polymorphida | Nickol et al. (1999); García-Varela & Pérez-Ponce de León (2008) | Polymorphidae. | ICZN |
| Progne | Passeriformes | Clements (2007) | . | ICZN |
| Progordius | Gordioidea | Schmidt-Rhaesa (2002); Poinar Jr. (2008) | . | ICZN |
| Proichthydioides | Chaetonotida | Balsamo et al. (2009) | . | ICZN |
| Proichthydium | Chaetonotida | Balsamo et al. (2009) | . | ICZN |
| Proiphys | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Projoenia | Cristamonadida | Cepicka et al. (2010) | . | ICZN |
| Prolagus | Lagomorpha | Hoffmann & Smith (2005) | Recently extinct. | ICZN |
| Prolemur | Primates | Groves (2005) | . | ICZN |
| Proleptomonas | Glissomonadida | Howe et al. (2009) | . | ICZN |
| Prolicnophora | Licnophorida | Lynn (2008) | . | ICZN |
| Prolinoborus | Neisseriales | Garrity et al. (2005) | . | ICNB |
| Prolixibacter | Bacteroidales | Holmes et al. (2007) | . | ICNB |
| Prolixoplecta | Lituolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Prolixoplectidae. | ICZN |
| Prolobus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Prolongoa | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Prolophomonas | Cristamonadida | Brugerolle & Lee (2000); Cepicka et al. (2010) | Possibly later synonym of Lophomonas. | ICZN |
| Promenaea | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Promerops | Passeriformes | Clements (2007) | . | ICZN |
| Prometheomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Prometheum | Saxifragales | Mabberley (2008) | Crassulaceae. | ICBN |
| Promicromonospora | Micrococcales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Promoniliformis | Moniliformida | Amin (1985) | . | ICZN |
| Promops | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Proneurotes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Pronolagus | Lagomorpha | McKenna & Bell (1997) | . | ICZN |
| Pronyctotherus | Clevelandellida | Lynn (2008) | . | ICZN |
| Propachycordyle | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Propionibacter | Rhodocyclales | Garrity et al. (2005) | . | ICNB |
| Propionibacterium | Propionibacteriales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Propionicicella | Propionibacteriales | Bae et al. (2006); Ludwig et al. (2012) | . | ICNB |
| Propioniciclava | Propionibacteriales | Sugawara et al. (2011); Ludwig et al. (2012) | Propionibacteriaceae. | ICNB |
| Propionicimonas | Propionibacteriales | Akasaka et al. (2003); Ludwig et al. (2012) | . | ICNB |
| Propioniferax | Propionibacteriales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Propionigenium | Fusobacteriales | Garrity et al. (2005) | . | ICNB |
| Propionimicrobium | Propionibacteriales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Propionispira | Selenomonadales | Garrity et al. (2005); Marchandin et al. (2010) | . | ICNB |
| Propionispora | Selenomonadales | Garrity et al. (2005); Marchandin et al. (2010) | . | ICNB |
| Propionivibrio | Rhodocyclales | Garrity et al. (2005) | . | ICNB |
| Propithecus | Primates | McKenna & Bell (1997) | . | ICZN |
| Proplagiopyxis | Arcellinida | Meisterfeld (2000) | Difflugina -- Centropyxidae. | ICZN |
| Proplectella | Tintinnida | Lynn (2008) | . | ICZN |
| Proporus | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Propsammonobiotus | Tectofilosida | Meisterfeld (2000); Cavalier-Smith & Chao (2003) | Psammonobiotidae. | ICZN |
| Proptychostomum | Thigmotrichida | Lynn (2008) | . | ICZN |
| Propygocirrus | Heterotrichida | Lynn (2008) | . | ICZN |
| Propyxidium | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Prorocentrum | Prorocentrales | Fensome et al. (1993) | . | ICBN |
| Prorodon | Prorodontida | Lynn (2008) | . | ICZN |
| Prorodonopsis | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Prosadenoporus | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Prosaptia | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Prosartes | Liliales | Mabberley (2008) | Liliaceae. | ICBN |
| Proscelotes | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Prosciurillus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Proscyllium | Carcharhiniformes | Nelson (2006) | . | ICZN |
| Proscymnodon | Squaliformes | Nelson (2006) | . | ICZN |
| Proserpinaca | Saxifragales | Mabberley (2008) | Haloragaceae. | ICBN |
| Prosicuophora | Clevelandellida | Lynn (2008) | . | ICZN |
| Proskauera | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Prosnyderella | Cristamonadida | Cepicka et al. (2010) | . | ICZN |
| Prosoaulax | Suessiales | Calado & Moestrup (2005) | Now checking. | ICBN |
| Prosobonia | Charadriiformes | Clements (2007) | . | ICZN |
| Prosopanche | Piperales | Mabberley (2008) | Hydnoraceae. | ICBN |
| Prosopeia | Psittaciformes | Clements (2007) | . | ICZN |
| Prosopidastrum | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Prosopis | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Prosorhochmus | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Prosphytochloa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Prostanthera | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Prostelidiella | Tintinnida | Lynn (2008) | . | ICZN |
| Prosthecea | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Prosthecidiscus | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Prosthecobacter | Verrucomicrobiales | Garrity et al. (2005) | . | ICNB |
| Prosthecochloris | Chlorobiales | Garrity et al. (2005) | . | ICNB |
| Prosthecomicrobium | Rhizobiales | Garrity et al. (2005) | . | ICNB |
| Prosthemadera | Passeriformes | Clements (2007) | . | ICZN |
| Prosthenorchis | Oligacanthorhynchida | Amin (1985) | . | ICZN |
| Prostobuccantia | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Prostoma | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Prostomatella | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Prostomiopsis | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Prosuberites | Hadromerida | Van Soest (2002) | . | ICZN |
| Prosymna | Squamata | Mattison (2007); Vitt & Caldwell (2009) | Serpentes. "Colubridae." Not "Prosyma". | ICZN |
| Protacanthamoeba | Centramoebida | Rogerson & Patterson (2000); Smirnov et al. (2005); Smirnov et al. (2011) | . | ICZN |
| Protanoplophrya | Thigmotrichida | Lynn (2008) | . | ICZN |
| Protanthea | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Protarum | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Protaspa | Cryomonadida | Howe et al. (2011) | . | ICZN |
| Protaspis | Cryomonadida | Howe et al. (2011) | Later homonym. Replaced by Protaspa. | ICZN |
| Protea | Proteales | Mabberley (2008) | Proteaceae. | ICBN |
| Proteiniborus | Clostridiales | Niu et al. (2008) | . | ICNB |
| Proteiniclasticum | Clostridiales | Zhang et al. (2010) | . | ICNB |
| Proteiniphilum | Bacteroidales | Chen & Dong (2005) | . | ICNB |
| Proteleia | Hadromerida | Boury-Esnault (2002) | . | ICZN |
| Proteles | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Proteocatella | Clostridiales | Pikuta et al. (2009) | . | ICNB |
| Proteomonas | Pyrenomonadales | Clay et al. (1999); Novarino (2003) | . | ICBN |
| Proteopsis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Proterendothrix | Oscillatoriales | Yamagishi (2007) | . | ICBN |
| Proteromonas | Proteromonadales | Cavalier-Smith & Chao (2006) | . | ICZN |
| Proterospongia | Craspedida | Leadbeater & Thomsen (2000) | . | ICZN |
| Proterythropsis | Gymnodiniales | Fensome et al. (1993) | . | ICBN |
| Protetrastemma | Eumonostilifera | Chernyshev (2004); Kajihara et al. (2008) | Tetrastemmatidae. Now checking. | ICZN |
| Proteus | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Proteus | Caudata | Vitt & Caldwell (2009) | Proteidae. | ICZN |
| Protiara | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Protium | Sapindales | Mabberley (2008) | Burseraceae. | ICBN |
| Protoachlya | Saprolegniales | Dick (2001); Kirk et al. (2008) | Saprolegniaceae. | ICBN |
| Protobotellina | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hippocrepinidae. | ICZN |
| Protobothrops | Squamata | Vitt & Caldwell (2009) | Serpentes. Viperidae. | ICZN |
| Protobremia | Peronosporales | Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Protocaviella | Vestibuliferida | Lynn (2008) | . | ICZN |
| Protocephalozia | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Protoceratium | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Protochromys | Rodentia | Musser & Carleton (2005) | . | ICZN |
| Protochrysis | Pyrenomonadales | Novarino (2003) | Allied to Hemiselmis ?. | ICBN |
| Protocruzia | Protocruziida | Lynn (2008) | . | ICZN |
| Protocryptomonas | | Novarino (2003) | Domain Eucarya - Kingdom Cryptobiontes ? - Phylum Cryptophyta ?. | ICBN |
| Protocyclidium | Pleuronematida | Lynn (2008) | . | ICZN |
| Protocymatocylis | Tintinnida | Lynn (2008) | . | ICZN |
| Protodinium | Suessiales | Fensome et al. (1993); Moestrup et al. (2009) | Phylogenetically included within the family Suessiaceae. | ICBN |
| Protoeukrohnia | Phragmophora | Kasatkina (2003) | Eukrohniidae. | ICZN |
| Protogastrostyla | | Gong et al. (2007) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora - Class Spirotrichea - Subclass Stichotrichia. | ICZN |
| Protogenes | | Bass et al. (2009) | Domain Eucarya - Rhizaria - incertae sedis - Family Rhizoplasmidae. | ICZN |
| Protoglobobulimina | Buliminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Buliminidae. | ICZN |
| Protoglossus | Helminthomorpha | Benito (1982); Deland et al. (2010) | Harrimaniidae. | ICZN |
| Protohallia | Vestibuliferida | Lynn (2008) | . | ICZN |
| Protoholozoa | Aplousobranchia | Monniot & Monniot (1972); Kott (1998); Monniot (2001) | Holozoidae. | ICZN |
| Protohydra | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Protohynobius | Caudata | Vitt & Caldwell (2009) | Hynobiidae. | ICZN |
| Protoisotricha | Vestibuliferida | Lynn (2008) | . | ICZN |
| Protokrohnittella | Phragmophora | Kasatkina (2003) | Krohnittellidae. | ICZN |
| Protokuetzingia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Protolophozia | Jungermanniales | Vilnet et al. (2008) | The generic status is uncertain. | ICBN |
| Protolutzia | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Protomagalhaensia | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Protomegabaria | Malpighiales | Mabberley (2008) | Phyllanthaceae. | ICBN |
| Protomolgula | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Molgulidae. | ICZN |
| Protomonas | Rhizobiales | Garrity et al. (2005) | . | ICNB |
| Protomyxa | | Bass et al. (2009) | Domain Eucarya - Rhizaria - incertae sedis - Family Rhizoplasmidae. | ICZN |
| Protonotaria | Passeriformes | Clements (2007) | . | ICZN |
| Protoodinium | | Fensome et al. (1993); Skovgaard et al. (2007) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Dinozoa - Class Dinophyceae. Former Blastodiniales. | ICBN |
| Protoopalina | Opalinales | Delvinquier & Patterson (2000) | . | ICZN |
| Protopalythoa | Zoanthidea | Sinniger et al. (2005) | . | ICZN |
| Protopelagonemertes | Pelagica | Gibson (1995) | . | ICZN |
| Protoperidinium | Peridiniales | Fensome et al. (1993) | . | ICBN |
| Protophryoglena | Ophryoglenida | Lynn (2008) | Later synonym of Ophryoglena. | ICZN |
| Protophyra | Thigmotrichida | Lynn (2008) | . | ICZN |
| Protophyropsis | Thigmotrichida | Lynn (2008) | . | ICZN |
| Protophysarum | Physarales | Yamamoto (1998) | . | ICBN |
| Protoplagiopyxis | Arcellinida | Meisterfeld (2000) | Difflugina -- Plagiopyxidae. | ICZN |
| Protopolyclinum | Aplousobranchia | Monniot & Monniot (1972); Kott (1998) | Protopolyclinidae. | ICZN |
| Protopsis | Gymnodiniales | Fensome et al. (1993) | . | ICBN |
| Protopterus | Ceratodontiformes | Nelson (2006) | . | ICZN |
| Protoptilum | Pennatulacea | Williams (1995) | . | ICZN |
| Protoptychostomum | Thigmotrichida | Lynn (2008) | . | ICZN |
| Protoradiophryopsis | Astomatida | Lynn (2008) | . | ICZN |
| Protorhabdonella | Tintinnida | Lynn (2008) | . | ICZN |
| Protorhus | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Protoschista | Lituolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Thomasinellidae. | ICZN |
| Protoschwenkia | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Protospathidium | Haptorida | Lynn (2008) | . | ICZN |
| Protospirella | Thigmotrichida | Lynn (2008) | . | ICZN |
| Protosporangium | Protosteliales | Olive (1975) | . | ICBN |
| Protosteliopsis | Protosteliales | Olive (1975) | . | ICBN |
| Protostelium | Protosteliales | Olive (1975) | . | ICBN |
| Protostyela | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Styelidae. | ICZN |
| Protosuberites | Hadromerida | Van Soest (2002) | . | ICZN |
| Protosyzygiella | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Prototapirella | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Prototheca | Chlorellales | Ueno et al. (2005); Neustupa et al. (2011) | As AHP lineage. | ICBN |
| Prototrachelocerca | Protostomatida | Lynn (2008) | . | ICZN |
| Prototravassosia | Astomatida | Lynn (2008) | . | ICZN |
| Prototrichia | Trichiales | Yamamoto (1998) | . | ICBN |
| Protowoodsia | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Protoxerus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Protozelleriella | Opalinales | Delvinquier & Patterson (2000) | . | ICZN |
| Protrichomonas | Tritrichomonadida | Cepicka et al. (2010) | . | ICZN |
| Protubulanus | Palaeonemertea | Kajihara et al. (2008) | . | ICZN |
| Proustia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Providencia | Enterobacteriales | Garrity et al. (2005) | . | ICNB |
| Proxifrons | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nodosariidae. | ICZN |
| Prumnopitys | Araucariales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Prunella | Passeriformes | Clements (2007) | . | ICZN |
| Prunella | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Prunus | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Prymnesium | Prymnesiales | Edvardsen et al. (2000); Jordan et al. (2004) | Prymnesiaceae. | ICBN |
| Przewalskia | Solanales | Mabberley (2008) | Solanaceae. | ICBN |
| Przewalskium | Artiodactyla | Grubb (2005) | . | ICZN |
| Psacaliopsis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psacalium | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psalidoprocne | Passeriformes | Clements (2007) | . | ICZN |
| Psalteriomonas | Lyromonadida | Cavalier-Smith (2003) | . | ICZN |
| Psaltria | Passeriformes | Clements (2007) | . | ICZN |
| Psaltriparus | Passeriformes | Clements (2007) | . | ICZN |
| Psammagrostis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Psammamphiporus | Eumonostilifera | Gibson (1995); Chernyshev (2003); Kajihara et al. (2008) | Junior synonym of Amphiporus. | ICZN |
| Psammascidia | Phlebobranchia | Monniot & Monniot (1972); Monniot (2001) | Ascidiidae. | ICZN |
| Psammastra | Astrophorida | Uriz (2002) | . | ICZN |
| Psammatodendron | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Rhabdamminidae. | ICZN |
| Psammetes | Lamiales | Mabberley (2008) | Phrymaceae. | ICBN |
| Psammetta | Psamminida | Gooday & Tendal (2000) | . | ICZN |
| Psammina | Psamminida | Gooday & Tendal (2000) | . | ICZN |
| Psammiosorus | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Psammisia | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Psammobates | Testudinata | Vitt & Caldwell (2009) | Testudinidae. | ICZN |
| Psammobatis | Rajiformes | Nelson (2006) | . | ICZN |
| Psammochela | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Psammochloa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Psammocinia | Dictyoceratida | Cook & Bergquist (2002) | . | ICZN |
| Psammoclema | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Psammocora | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Psammodromus | Squamata | Vitt & Caldwell (2009) | Lacertidae. | ICZN |
| Psammodynastes | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Psammogeton | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Psammogorgia | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Psammohydra | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Psammomitra | Urostylida | Lynn (2008) | Later synonym of Uroleptus?. | ICZN |
| Psammomoya | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Psammomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Psammonobiotus | Tectofilosida | Meisterfeld (2000); Cavalier-Smith & Chao (2003) | Psammonobiotidae. | ICZN |
| Psammonyx | Lituolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ammodiscidae. | ICZN |
| Psammophaga | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Saccamminidae. | ICZN |
| Psammophax | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Psammosphaeridae. | ICZN |
| Psammophilus | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Psammophis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Psammophora | Caryophyllales | Mabberley (2008) | Aizoaceae. | ICBN |
| Psammophylax | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Psammosphaera | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Psammosphaeridae. | ICZN |
| Psammostyela | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Styelidae. | ICZN |
| Psammotropha | Caryophyllales | Mabberley (2008) | Molluginaceae. | ICBN |
| Psarisomus | Passeriformes | Clements (2007) | . | ICZN |
| Psarocolius | Passeriformes | Clements (2007) | . | ICZN |
| Psaromenia | Gigartinales | Wynne & Schneider (2010) | . | ICBN |
| Psathura | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Psathyrostachys | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Psathyrotes | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psathyrotopsis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psednotrichia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseliodinium | | Fensome et al. (1993) | Domain Eucarya - Phylum Dinozoa - Class Dinophyceae. | ICBN |
| Pselliophorus | Passeriformes | Clements (2007) | . | ICZN |
| Psephotus | Psittaciformes | Clements (2007) | . | ICZN |
| Pseudablabes | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudabutilon | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pseudacidovorax | Burkholderiales | Kämpfer et al. (2008) | . | ICNB |
| Pseudacris | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Pseudactinia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Pseudactinoposthia | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Pseudadercotryma | Trochamminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Trochamminidae. | ICZN |
| Pseudaechmea | Poales | Mabberley (2008) | Bromeliaceae. | ICBN |
| Pseudagkistrodon | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudagrostistachys | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pseudahrensia | Rhizobiales | Jung et al. (2012) | . | ICNB |
| Pseudaidia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pseudalaemon | Passeriformes | Clements (2007) | . | ICZN |
| Pseudalopex | Carnivora | McKenna & Bell (1997); Wozencraft (2005) | Later synonym of Lycalopex. | ICZN |
| Pseudalthenia | Alismatales | Mabberley (2008) | Potamogetonaceae. | ICBN |
| Pseudaminobacter | Rhizobiales | Garrity et al. (2005) | . | ICNB |
| Pseudanabaena | Pseudanabaenales | Hoffmann et al. (2005) | . | ICBN |
| Pseudananas | Poales | Mabberley (2008) | Bromeliaceae. | ICBN |
| Pseudanaperus | Acoela | Dörjes (1968) | . | ICZN |
| Pseudantechinus | Dasyuromorphia | Groves (2005) | . | ICZN |
| Pseudanthistiria | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudanthus | Malpighiales | Mabberley (2008) | Picrodendraceae. | ICBN |
| Pseudaphanostoma | Acoela | Dörjes (1968); Faubel & Noreña (2001); Hooge & Tyler (2005) | . | ICZN |
| Pseudaphelidium | Aphelidida | Gromov (2000) | . | ICZN |
| Pseudarcicella | Cytophagales | Kämpfer et al. (2012) | . | ICNB |
| Pseudartabotrys | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Pseudarthria | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudaspis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudatrichum | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Pseudauchen | Echinorhynchida | Amin (1985) | . | ICZN |
| Pseudawerintzewia | Arcellinida | Meisterfeld (2000) | incertae sedis. | ICZN |
| Pseudechiniscus | Echiniscoidea | Kinchin (1994) | . | ICZN |
| Pseudechinolaena | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudechis | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Pseudelaenia | Passeriformes | Clements (2007) | . | ICZN |
| Pseudelephantopus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudeminia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudemoia | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Pseudemydura | Testudinata | Vitt & Caldwell (2009) | Chelidae. | ICZN |
| Pseudemys | Testudinata | Vitt & Caldwell (2009) | Emydidae. | ICZN |
| Pseudeos | Psittaciformes | Clements (2007) | . | ICZN |
| Pseudephedranthus | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Pseudephemerum | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Pseudepidalea | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Pseudepistylis | Peritrichida | Peng et al. (2007) | . | ICZN |
| Pseuderanthemum | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pseuderemias | Squamata | Vitt & Caldwell (2009) | Lacertidae. | ICZN |
| Pseuderemostachys | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pseuderia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pseuderucaria | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudeugenia | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Pseudeukrohnia | Phragmophora | Kasatkina & Stolyarova (2006) | Eukrohniidae. | ICZN |
| Pseudhirundo | Passeriformes | Clements (2007) | . | ICZN |
| Pseudhormathia | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Pseudhymenochirus | Anura | Vitt & Caldwell (2009) | Pipidae. | ICZN |
| Pseudibis | Ciconiiformes | Clements (2007) | . | ICZN |
| Pseudicyema | Dicyemida | Stunkard (1982); Furuya et al. (2007) | . | ICZN |
| Pseudidiomarina | Alteromonadales | Jean et al. (2006); Taborda et al. (2009) | Later synonym of Idiomarina. | ICNB |
| Pseudima | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Pseudiosma | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pseudis | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Pseudmecynostomum | Acoela | Dörjes (1968); Faubel & Noreña (2001) | Also spelled as "Pseudomecynostomum" in the original description. | ICZN |
| Pseudoacanthocephalus | Echinorhynchida | Amin (1985) | . | ICZN |
| Pseudoacanthocereus | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pseudoacontias | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Pseudoalatospora | Bivalvulida | Lom & Dyková (2006) | . | ICZN |
| Pseudoalcippe | Passeriformes | Clements (2007) | . | ICZN |
| Pseudoalteromonas | Alteromonadales | Garrity et al. (2005) | . | ICNB |
| Pseudoamphileptus | Pleurostomatida | Lynn (2008) | . | ICZN |
| Pseudoamphisiella | Urostylida | Lynn (2008) | . | ICZN |
| Pseudoanthomastus | Alcyonacea | Verseveldt & Bayer (1988) | Alcyoniidae. | ICZN |
| Pseudoarabidopsis | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudobaeckea | Bruniales | Mabberley (2008) | Bruniaceae. | ICBN |
| Pseudobahia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudobakuella | Urostylida | Lynn (2008) | . | ICZN |
| Pseudobambusa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudobangia | Bangiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudobaseodiscus | Heteronemertea | Gibson (1995) | . | ICZN |
| Pseudobetckea | Dipsacales | Mabberley (2008) | Caprifoliaceae. | ICBN |
| Pseudobias | Passeriformes | Clements (2007) | . | ICZN |
| Pseudobiotus | Parachela | Kinchin (1994) | . | ICZN |
| Pseudoblepharisma | Heterotrichida | Lynn (2008) | . | ICZN |
| Pseudoblepharispermum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudoboa | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudobodo | | Cavalier-Smith & Chao (2006) | Domain Eucarya - Kingdom Straminipila - Phylum Bicosoecacea - Class Bicoecea. | ICZN |
| Pseudobolivina | Lituolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pseudobolivinidae. | ICZN |
| Pseudobombax | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pseudoboodon | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudobotrys | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Pseudobranchioglossum | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudobranchus | Caudata | Vitt & Caldwell (2009) | Sirenidae. | ICZN |
| Pseudobraunia | Hedwigiales | Goffinet et al. (2009) | . | ICBN |
| Pseudobrickellia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudobryum | Bryales | Goffinet et al. (2009) | . | ICBN |
| Pseudobuetschlia | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Pseudobufo | Anura | Vitt & Caldwell (2009) | Bufonidae. | ICZN |
| Pseudobulimina | Robertinida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Robertinidae. | ICZN |
| Pseudobumilleriopsis | Mischococcales | Ettl (1978); Maistro et al. (2009) | . | ICBN |
| Pseudobutyrivibrio | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Pseudocaedibacter | Rickettsiales | Garrity et al. (2005) | . | ICNB |
| Pseudocalliergon | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudocalotes | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Pseudocalyptomena | Passeriformes | Clements (2007) | . | ICZN |
| Pseudocalyx | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pseudocamelina | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudocancris | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Bagginidae. | ICZN |
| Pseudocannaboides | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pseudocapsa | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Pseudocarcharias | Lamniformes | Nelson (2006) | . | ICZN |
| Pseudocarchesium | Peritrichida | Lynn (2008); Zhan et al. (2009) | Nomen nudum. | ICZN |
| Pseudocarcinonemertes | Eumonostilifera | Gibson (1995); Chernyshev (2003) | . | ICZN |
| Pseudocarpidium | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pseudocarum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pseudocaryopteris | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pseudocatalpa | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Pseudocavisoma | Echinorhynchida | Amin (1985) | . | ICZN |
| Pseudocedrela | Sapindales | Mabberley (2008) | Meliaceae. | ICBN |
| Pseudocentrum | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pseudocephalozia | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pseudocephaloziella | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pseudocerastes | Squamata | Vitt & Caldwell (2009) | Serpentes. Viperidae. | ICZN |
| Pseudocerastium | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pseudoceratina | Verongida | Bergquist & Cook (2002) | . | ICZN |
| Pseudochaetochloa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudochantransia | | Schneider & Wynne (2007) | . | ICBN |
| Pseudocharaciopsis | Eustigmatales | Hibberd (1981): Hegewald et al. (2007) | . | ICBN |
| Pseudochattonella | Florenciellales | Hosoi-Tanabe et al. (2007); Edvardsen et al. (2007); Eikrem et al. (2009) | . | ICBN |
| Pseudocheirus | Australidelphia | McKenna & Bell (1997) | . | ICZN |
| Pseudochelidon | Passeriformes | Clements (2007) | . | ICZN |
| Pseudochilodonopsis | Chlamydodontida | Lynn (2008) | . | ICZN |
| Pseudochirita | Lamiales | Mabberley (2008) | Gesneriaceae. | ICBN |
| Pseudochirops | Diprotodontia | Groves (2005) | . | ICZN |
| Pseudochirulus | Diprotodontia | Groves (2005) | . | ICZN |
| Pseudochlamydonella | Cyrtolophosidida | Lynn (2008) | . | ICZN |
| Pseudochlorella | Prasiolales | Neustupa et al. (2009) | As Prasiola clade. | ICBN |
| Pseudochloroptila | Passeriformes | Clements (2007) | . | ICZN |
| Pseudochordodes | Gordioidea | Schmidt-Rhaesa (2002); Poinar Jr. (2008) | . | ICZN |
| Pseudochorisodontium | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Pseudochrobactrum | Rhizobiales | Kämpfer et al. (2006) | . | ICNB |
| Pseudocinetochilum | Philasterida | Lynn (2008) | . | ICZN |
| Pseudocirrhipathes | Antipatharia | Bo et al. (2009) | "110608". | ICZN |
| Pseudocladochonus | Alcyonacea | Bayer (1981) | Clavulariidae. | ICZN |
| Pseudoclappia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudoclathrozoon | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Pseudoclausena | Sapindales | Mabberley (2008) | Meliaceae. | ICBN |
| Pseudoclausia | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudoclavibacter | Micrococcales | Manaia et al. (2004); Ludwig et al. (2012) | . | ICNB |
| Pseudoclytia | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Pseudocohnilembus | Philasterida | Lynn (2008) | . | ICZN |
| Pseudocolaptes | Passeriformes | Clements (2007) | . | ICZN |
| Pseudocolopteryx | Passeriformes | Clements (2007) | . | ICZN |
| Pseudocolpodidium | Nassulida | Lynn & Small (2000); Lynn (2008); Breiner et al. (2008) | . | ICZN |
| Pseudoconnarus | Oxalidales | Mabberley (2008) | Connaraceae. | ICBN |
| Pseudoconvoluta | Acoela | Dörjes (1968) | . | ICZN |
| Pseudoconyza | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudocorchorus | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pseudocorticium | Homosclerophorida | Muricy & Díaz (2002) | . | ICZN |
| Pseudocorynactis | Corallimorpharia | Fautin et al. (2007); Fautin (2011) | Junior synonym of Corynactis. | ICZN |
| Pseudocorynosoma | Polymorphida | Aznar et al. (2006) | Polymorphidae. | ICZN |
| Pseudocorythion | Euglyphida | Meisterfeld (2000) | . | ICZN |
| Pseudocossyphus | Passeriformes | Clements (2007) | . | ICZN |
| Pseudocranichis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pseudocrossidium | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Pseudocrouania | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudocryphaea | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudocrypthelia | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pseudocryptomonas | Cryptomonadales | Hoef-Emden & Melkonian (2003); Novarino (2003) | Later synonym of Cryptomonas. | ICBN |
| Pseudocubus | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Pseudocyathoceras | Scleractinia | Cairns et al. (1999) | . | ICZN |
| Pseudocyclanthera | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Pseudocyclidium | Pleuronematida | Lynn (2008) | . | ICZN |
| Pseudocyclophis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudocydonia | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Pseudocymopterus | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pseudocyrtolophosis | Cyrtolophosidida | Lynn (2008) | . | ICZN |
| Pseudodacnis | Passeriformes | Clements (2007) | . | ICZN |
| Pseudodacryodes | Sapindales | Mabberley (2008) | Burseraceae. | ICBN |
| Pseudodanthonia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudodendromonas | Pseudodendromonadales | Cavalier-Smith & Chao (2006) | . | ICZN |
| Pseudodevescovina | Cristamonadida | Cepicka et al. (2010) | . | ICZN |
| Pseudodiazona | Aplousobranchia | Monniot & Monniot (1972); Kott (1998); Monniot (2001) | Diazonidae. | ICZN |
| Pseudodichanthium | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudodicliptera | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pseudodidymium | Physarales | Michel et al. (2003); Fiore-Donno et al. (2010) | Later synonym of Didymium. | ICBN |
| Pseudodifflugia | Tectofilosida | Meisterfeld (2000); Cavalier-Smith & Chao (2003) | Pseudodifflugiidae. | ICZN |
| Pseudodimorpha | | Bass et al. (2009) | Domain Eucarya - Phylum Cercozoa - Class Granofilosea. | ICZN |
| Pseudodiophrys | Euplotida | Jiang et al. (2011) | . | ICZN |
| Pseudodiphascon | Parachela | Kinchin (1994) | . | ICZN |
| Pseudodissochaeta | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pseudodistoma | Aplousobranchia | Monniot & Monniot (1972); Kott (1998); Monniot (2001) | Pseudodistomidae. | ICZN |
| Pseudoditrema | Allogromiida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Lagynidae. | ICZN |
| Pseudoditrichum | Bryales | Goffinet et al. (2009) | . | ICBN |
| Pseudodrifa | Alcyonacea | Bayer (1981) | Nephtheidae. | ICZN |
| Pseudoduganella | Burkholderiales | Kämpfer et al. (2012) | . | ICNB |
| Pseudoentodinium | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Pseudoeponides | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Epistomariidae. | ICZN |
| Pseudoeriosema | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudoernestia | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pseudoerythrocladia | Erythropeltidales | Wynne & Schneider (2010) | . | ICBN |
| Pseudoeryx | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudoeurycea | Caudata | Vitt & Caldwell (2009) | Plethodontidae. | ICZN |
| Pseudoficimia | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudofissurina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ellipsolagenidae. | ICZN |
| Pseudoflavonifractor | Clostridiales | Carlier et al. (2010) | . | ICNB |
| Pseudoflintina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Pseudofolliculina | Heterotrichida | Lynn (2008) | . | ICZN |
| Pseudofortuynia | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudofulvimonas | Xanthomonadales | Kämpfer et al. (2010) | . | ICNB |
| Pseudofumaria | Ranunculales | Mabberley (2008) | Papaveraceae. | ICBN |
| Pseudogaudryina | Textulariida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pseudogaudryinidae. | ICZN |
| Pseudogekko | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Pseudogemma | Endogenida | Lynn (2008) | . | ICZN |
| Pseudogemmides | Exogenida | Lynn (2008) | . | ICZN |
| Pseudoginglymostoma | Orectolobiformes | Nelson (2006) | . | ICZN |
| Pseudoglaucoma | Colpodida | Lynn (2008) | . | ICZN |
| Pseudognaphalium | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudogomphrena | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pseudogonatodes | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Pseudogoodyera | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pseudogordiorhynchus | Polymorphida | Amin (1985) | . | ICZN |
| Pseudogordius | Gordioidea | Schmidt-Rhaesa (2002); Poinar Jr. (2008) | . | ICZN |
| Pseudogorgia | Alcyonacea | Bayer (1981) | Pseudogorgiidae. | ICZN |
| Pseudogrinnellia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudogulbenkiania | Neisseriales | Lin et al. (2008) | . | ICNB |
| Pseudogynoxys | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudohaje | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Pseudohalichondria | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Pseudohalopeltis | Rhodymeniales | Wynne & Schneider (2010) | . | ICBN |
| Pseudohamelia | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pseudohandelia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudohaplocaulus | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Pseudohaplogonaria | Acoela | Dörjes (1968); Faubel & Noreña (2001) | . | ICZN |
| Pseudoharringia | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Pseudohauerina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Riveroinidae. | ICZN |
| Pseudohauerinella | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Riveroinidae. | ICZN |
| Pseudohelenina | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Heleninidae. | ICZN |
| Pseudohemisincirra | | Foissner et al. (2008) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora - Class Spirotrichea - Subclass Stichotrichia. | ICZN |
| Pseudoholophrya | Haptorida | Lynn (2008) | . | ICZN |
| Pseudohydromys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pseudohydrosme | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Pseudohygrohypnum | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudohynobius | Caudata | Vitt & Caldwell (2009) | Hynobiidae. | ICZN |
| Pseudohyophila | Dicranales | Goffinet et al. (2009) | . | ICBN |
| Pseudohypnella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudois | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Artiodactyla. | ICZN |
| Pseudokahliella | Stichotrichida | Lynn (2008) | . | ICZN |
| Pseudokephyrion | Ochromonadales | Kristiansen & Preisig (2001); Cavalier-Smith & Chao (2006) | Dinobryaceae (biflagellate). | ICBN |
| Pseudokeronopsis | Urostylida | Lynn (2008) | . | ICZN |
| Pseudokineococcus | Kineosporiales | Jurado et al. (2011); Ludwig et al. (2012) | Kineosporiaceae. | ICNB |
| Pseudoklossia | Eucoccidiorida | Perkins et al. (2000) | . | ICZN |
| Pseudokreyella | Bursariomorphida | Lynn (2008); Foissner et al. (2011) | . | ICZN |
| Pseudokuma | Acoela | Dörjes (1968) | . | ICZN |
| Pseudolabrys | Rhizobiales | Kämpfer et al. (2006) | . | ICNB |
| Pseudolachnostylis | Malpighiales | Mabberley (2008) | Phyllanthaceae. | ICBN |
| Pseudolaelia | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pseudolaingia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudolarix | Pinales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Pseudoleistes | Passeriformes | Clements (2007) | . | ICZN |
| Pseudolepicolea | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pseudoleptodeira | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudoleptorhynchoides | Echinorhynchida | Amin (1985) | . | ICZN |
| Pseudoleskea | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudoleskeella | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudoleskeopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudolingulina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nodosariidae. | ICZN |
| Pseudolithium | Symphyacanthida | Febvre et al. (2000) | . | ICZN |
| Pseudolithophyllum | Corallinales | Schneider & Wynne (2007) | Later synonym of Lithophyllum. | ICBN |
| Pseudolithos | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pseudolmedia | Rosales | Mabberley (2008) | Moraceae. | ICBN |
| Pseudoloma | Microsporida | Matthews et al. (2001) | . | ICZN |
| Pseudolophocolea | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pseudolotus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudolueheia | Polymorphida | Amin (1985) | . | ICZN |
| Pseudomacrolobium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudomalmea | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Pseudomantalania | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pseudomarrubium | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pseudomarvania | Prasiolales | Eliáš & Neustupa (2009) | As Stichococcus/Raphidonema clade. | ICBN |
| Pseudomaryna | Colpodida | Lynn (2008) | . | ICZN |
| Pseudomassilina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Pseudomelasma | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Pseudomertensia | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pseudometacylis | Tintinnida | Lynn (2008) | . | ICZN |
| Pseudomicrothorax | Microthoracida | Lynn (2008) | . | ICZN |
| Pseudomisopates | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Pseudomonas | Pseudomonadales | Garrity et al. (2005) | . | ICNB |
| Pseudomonilicaryon | Haptorida | Lynn (2008) | . | ICZN |
| Pseudomonotes | Malvales | Mabberley (2008) | Dipterocarpaceae. | ICBN |
| Pseudomussaenda | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pseudomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pseudonaja | Squamata | Vitt & Caldwell (2009) | Serpentes. Elapidae. | ICZN |
| Pseudoncobyrsa | Chroococcales | Hoffmann et al. (2005) | . | ICBN |
| Pseudonebela | Arcellinida | Meisterfeld (2000) | incertae sedis. | ICZN |
| Pseudonemacladus | Asterales | Mabberley (2008) | Campanulaceae. | ICBN |
| Pseudonesohedyotis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pseudonestor | Passeriformes | Clements (2007) | . | ICZN |
| Pseudonigrita | Passeriformes | Clements (2007) | . | ICZN |
| Pseudonitophylla | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudonocardia | Pseudonocardiales | Garrity et al. (2005); Ludwig et al. (2012) | . | ICNB |
| Pseudonodosaria | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nodosariidae. | ICZN |
| Pseudonodosinella | Lituolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hormosinidae. | ICZN |
| Pseudononion | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nonionidae. | ICZN |
| Pseudonosema | Microsporida | Canning et al. (2002) | . | ICZN |
| Pseudonoseris | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudoolina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ellipsolagenidae. | ICZN |
| Pseudopaludicola | Anura | Vitt & Caldwell (2009) | Leiuperidae. | ICZN |
| Pseudopanax | Apiales | Mabberley (2008) | Araliaceae. | ICBN |
| Pseudopancovia | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Pseudoparactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Pseudoparafolliculina | Heterotrichida | Lynn (2008) | . | ICZN |
| Pseudoparamoeba | Dactylopodida | Rogerson & Patterson (2000); Smirnov et al. (2005) | . | ICZN |
| Pseudoparis | Commelinales | Mabberley (2008) | Commelinaceae. | ICBN |
| Pseudoparrella | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pseudoparrellidae. | ICZN |
| Pseudopedicellina | Coloniales | Emschermann (1972) | Barentsiidae. | ICZN |
| Pseudopedinella | Pedinellales | Moestrup (2000); Sekiguchi et al. (2003) | . | ICBN |
| Pseudopentameris | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudoperanema | Heteronematales | Leedale (1967); Larsen & Patterson (1991); Leedale (2000) | . | ICBN |
| Pseudoperkinsus | Ichthyophonida | Mendoza et al. (2002) | . | ICZN |
| Pseudoperonospora | Peronosporales | Dick (2001); Kirk et al. (2008) | Peronosporaceae. | ICBN |
| Pseudopfiesteria | Peridiniales | Litaker et al. (2005) | . | ICBN |
| Pseudophalacroma | Dinophysiales | Fensome et al. (1993) | . | ICBN |
| Pseudophegopteris | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pseudophilautus | Anura | Samarasinghe (2011) | Rhacophoridae. | ICZN |
| Pseudophoenix | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Pseudophormidium | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Pseudophryne | Anura | Vitt & Caldwell (2009) | Myobatrachidae. | ICZN |
| Pseudophycodrys | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudopiptadenia | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudopiptocarpha | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudopirsonia | Marimonadida | Howe et al. (2011) | . | ICZN |
| Pseudoplagiopyla | Plagiopylida | Lynn (2008) | . | ICZN |
| Pseudoplantago | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pseudoplatynematum | Philasterida | Lynn (2008) | . | ICZN |
| Pseudoplatyophrya | Colpodida | Lynn (2008) | . | ICZN |
| Pseudoplectella | Lyssacinosida | Tabachnick (2002) | . | ICZN |
| Pseudopleistophora | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Pseudopleurochloris | Mischococcales | Andreoli et al. (1999) | Closely related to Pleurochloris and Botrydiopsis. | ICBN |
| Pseudopleuropus | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudoplexaura | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Pseudoploesoma | Ploima | Segers (2002); Segers (2007) | . | ICZN |
| Pseudoplumarella | Alcyonacea | Bayer (1981) | Primnoidae. | ICZN |
| Pseudoplumaria | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Pseudopodoces | Passeriformes | Clements (2007) | . | ICZN |
| Pseudopogonatherum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudopohlia | Bryales | Goffinet et al. (2009) | . | ICBN |
| Pseudopolyedriopsis | Mischococcales | Ettl (1978) | . | ICBN |
| Pseudopolymorphina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Polymorphinidae. | ICZN |
| Pseudoposthia | Acoela | Dörjes (1968); Faubel & Noreña (2001); Hooge & Tyler (2005) | . | ICZN |
| Pseudopotto | Primates | McKenna & Bell (1997) | . | ICZN |
| Pseudoprosopis | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudoprospero | Asparagales | Mabberley (2008) | Asparagaceae. | ICBN |
| Pseudopteris | Sapindales | Mabberley (2008) | Sapindaceae. | ICBN |
| Pseudopterobryum | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudopterogorgia | Alcyonacea | Bayer (1981) | Gorgoniidae. | ICZN |
| Pseudopus | Squamata | Vitt & Caldwell (2009) | Anguidae. | ICZN |
| Pseudopyrgo | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Pseudopyxis | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pseudorabdion | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudoracelopus | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Pseudoraja | Rajiformes | Nelson (2006) | . | ICZN |
| Pseudoramibacter | Clostridiales | Garrity et al. (2005) | . | ICNB |
| Pseudorana | Anura | Vitt & Caldwell (2009) | Ranidae. | ICZN |
| Pseudoraphidiophrys | Acanthocystida | Mikrjukov et al. (2000); Cavalier-Smith & von der Heyden (2007); Yabuki et al. (2012) | Raphidiophryidae. | ICZN |
| Pseudoraphidocystis | Acanthocystida | Mikrjukov et al. (2000); Cavalier-Smith & von der Heyden (2007); Yabuki et al. (2012) | Acanthocystidae. Yabuki et al. (2012) spelled "Pseudoraphidiocystis". | ICZN |
| Pseudoraphis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudorca | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Cetacea. | ICZN |
| Pseudorchis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pseudorhadinorhynchus | Echinorhynchida | Amin (1985) | . | ICZN |
| Pseudorhipsalis | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pseudorhiza | Rhizostomeae | Kramp (1961) | . | ICZN |
| Pseudorhodobacter | Rhodobacterales | Garrity et al. (2005) | . | ICNB |
| Pseudorhododiscus | Palmariales | Schneider & Wynne (2007) | . | ICBN |
| Pseudorhodoferax | Burkholderiales | Bruland et al. (2009) | . | ICNB |
| Pseudorlaya | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pseudoroegneria | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudorontium | Lamiales | Mabberley (2008) | Plantaginaceae. | ICBN |
| Pseudorotalia | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Rotaliidae. | ICZN |
| Pseudoruegeria | Rhodobacterales | Yoon et al. (2007) | . | ICNB |
| Pseudoruellia | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pseudoryx | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Artiodactyla. | ICZN |
| Pseudoryzomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pseudosabicea | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pseudosagitta | Aphragmophora | Bieri (1991) | Sagittidae. | ICZN |
| Pseudosalacia | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Pseudosamanea | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudosasa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudosbeckia | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pseudoscabiosa | Dipsacales | Mabberley (2008) | Caprifoliaceae. | ICBN |
| Pseudoschlumbergerina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Pseudoschoenus | Poales | Mabberley (2008) | Cyperaceae. | ICBN |
| Pseudosclerochloa | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudoscleropodium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudoscolopia | Malpighiales | Mabberley (2008) | Salicaceae. | ICBN |
| Pseudoscops | Strigiformes | Clements (2007) | . | ICZN |
| Pseudoscourfieldia | Pseudoscourfieldiales | Melkonian (1990); Moestrup (2000); Guillou et al. (2004); Nakayama et al. (2007) | . | ICBN |
| Pseudoscytonema | Oscillatoriales | Hoffmann et al. (2005) | . | ICBN |
| Pseudosedum | Saxifragales | Mabberley (2008) | Crassulaceae. | ICBN |
| Pseudoseisura | Passeriformes | Clements (2007) | . | ICZN |
| Pseudoselago | Lamiales | Mabberley (2008) | Scrophulariaceae. | ICBN |
| Pseudoselinum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pseudosempervivum | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudosenefeldera | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pseudosericocoma | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Pseudosicydium | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Pseudosiderastrea | Scleractinia | Cairns et al. (1999); Veron (2000) | . | ICZN |
| Pseudosmelia | Malpighiales | Mabberley (2008) | Salicaceae. | ICBN |
| Pseudosmodingium | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pseudosolanderia | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pseudosolenina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ellipsolagenidae. | ICZN |
| Pseudosopubia | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Pseudosorghum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudosphaerita | Rozellopsidales | Dick (2001); Kirk et al. (2008) | Pseudosphaeritaceae. | ICBN |
| Pseudosphingobacterium | Sphingobacteriales | Vaz-Moreira et al. (2007) | . | ICNB |
| Pseudospiridentopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudospirillum | Oceanospirillales | Garrity et al. (2005) | . | ICNB |
| Pseudospondias | Sapindales | Mabberley (2008) | Anacardiaceae. | ICBN |
| Pseudospongosorites | Hadromerida | Van Soest (2002) | . | ICZN |
| Pseudospora | Pseudosporida | Cavalier-Smith (1993); Bass et al. (2009) | . | ICZN |
| Pseudospora | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pseudosporangium | Micromonosporales | Ara et al. (2008); Ludwig et al. (2012) | . | ICNB |
| Pseudostachyum | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseudostaurastrum | Eustigmatales | Hegewald et al. (2007) | . | ICBN |
| Pseudostellaria | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pseudostifftia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pseudostomella | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Pseudostriga | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Pseudostrombidium | | Lynn (2008) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Ciliophora - Class Spirotrichea. Sporadotrichida or Strombidiida. | ICZN |
| Pseudostygarctus | Arthrotardigrada | Kinchin (1994) | . | ICZN |
| Pseudosuberites | Hadromerida | Van Soest (2002) | . | ICZN |
| Pseudosymblepharis | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Pseudosyncrypta | Synurales | Kristiansen & Preisig (2001) | Synuraceae. | ICBN |
| Pseudotaxiphyllum | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudotaxus | Cupressales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Pseudoteredinibacter | Alteromonadales | Chen et al. (2011) | . | ICNB |
| Pseudotetraedriella | Eustigmatales | Hegewald et al. (2007) | Pseudotetraëdriella. | ICBN |
| Pseudotetraedron | Mischococcales | Ettl (1978) | Pseudotetraëdron. | ICBN |
| Pseudotetrastemma | | Kajihara et al. (2008) | Domain Eucarya - Kingdom Animalia - Phylum Nemertea - Class Hoplonemertea - Subclass Monostilifera. Now checking. | ICZN |
| Pseudothecadactylus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Pseudothecadinium | Gonyaulacales | Hoppenrath & Selina (2006) | Now checking. | ICBN |
| Pseudothecamoeba | | Rogerson & Patterson (2000); Cavalier-Smith et al. (2004); Smirnov et al. (2011) | Domain Eucarya - Phylum Amoebozoa - Subphylum Lobosa. | ICZN |
| Pseudothelogorgia | Alcyonacea | van Ofwegen (1994) | Keroeididae. | ICZN |
| Pseudothesea | Alcyonacea | Bayer (1981) | Plexauridae. | ICZN |
| Pseudothurammina | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Saccamminidae. | ICZN |
| Pseudothuricola | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Pseudotiara | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pseudotomodon | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudotontonia | Strombidiida | Lynn (2008) | . | ICZN |
| Pseudotrachelocerca | Haptorida | Lynn (2008) | . | ICZN |
| Pseudotrachya | Hadromerida | Boury-Esnault (2002) | . | ICZN |
| Pseudotrachydium | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pseudotrachypus | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudotrapelus | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Pseudotriakis | Carcharhiniformes | Nelson (2006) | . | ICZN |
| Pseudotriccus | Passeriformes | Clements (2007) | . | ICZN |
| Pseudotrichomonas | Trichomonadida | Cepicka et al. (2010); Yubuki et al. (2010) | . | ICZN |
| Pseudotrichonympha | Trichonymphida | Cepicka et al. (2010) | . | ICZN |
| Pseudotrillium | Liliales | Mabberley (2008) | Melanthiaceae. | ICBN |
| Pseudotriloculina | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Pseudotrimezia | Asparagales | Mabberley (2008) | Iridaceae. | ICBN |
| Pseudotrismegistia | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pseudotriton | Caudata | Vitt & Caldwell (2009) | Plethodontidae. | ICZN |
| Pseudotrochammina | Trochamminida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Trochamminidae. | ICZN |
| Pseudotrypanosoma | Trichomonadida | Cepicka et al. (2010) | . | ICZN |
| Pseudotsuga | Pinales | Farjon (2001); Christenhusz et al. (2011) | . | ICBN |
| Pseudoturbanella | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Pseudoturritis | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudotyphlops | Squamata | Vitt & Caldwell (2009) | Serpentes. Uropeltidae. | ICZN |
| Pseudouroleptus | Stichotrichida | Lynn (2008) | . | ICZN |
| Pseudourostyla | Urostylida | Lynn (2008) | . | ICZN |
| Pseudovahlkampfia | Schizopyrenida | Patterson et al. (2000) | . | ICZN |
| Pseudovanilla | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pseudovesicaria | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pseudovibrio | Rhodobacterales | Shieh et al. (2004) | . | ICNB |
| Pseudovigna | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pseudovorticella | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Pseudowebbinella | Astrorhizida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hemisphaeramminidae. | ICZN |
| Pseudoweinmannia | Oxalidales | Mabberley (2008) | Cunoniaceae. | ICBN |
| Pseudowintera | Canellales | Mabberley (2008) | Winteraceae. | ICBN |
| Pseudoxandra | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Pseudoxanthobacter | Rhizobiales | Arun et al. (2008) | . | ICNB |
| Pseudoxanthomonas | Xanthomonadales | Garrity et al. (2005) | . | ICNB |
| Pseudoxenodon | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudoxyrhopus | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pseudozobellia | Flavobacteriales | Nedashkovskaya et al. (2009) | . | ICNB |
| Pseudozoysia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pseuduronema | Philasterida | Lynn (2008) | . | ICZN |
| Pseuduvaria | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Pseustes | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Psiadia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psiadiella | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psidium | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Psiguria | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Psilactis | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psilanthele | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Psilanthus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Psilocalyx | Hexactinosida | Reiswig (2002) | . | ICZN |
| Psilocarphus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psilochilus | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Psiloclada | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Psilolaemus | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Psilolemma | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Psilopeganum | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Psilophthalmus | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Psilophycus | Gigartinales | Nelson et al. (2011) | . | ICBN |
| Psilopilum | Polytrichales | Goffinet et al. (2009) | . | ICBN |
| Psilopogon | Piciformes | Clements (2007) | . | ICZN |
| Psilopsiagon | Psittaciformes | Clements (2007) | . | ICZN |
| Psilorhamphus | Passeriformes | Clements (2007) | . | ICZN |
| Psilosiphon | Batrachospermales | Schneider & Wynne (2007) | . | ICBN |
| Psilostrophe | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psilothallia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Psilotricha | Stichotrichida | Lynn (2008) | . | ICZN |
| Psilotrichopsis | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Psilotrichum | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Psilotrix | Stichotrichida | Lynn (2008) | . | ICZN |
| Psilotum | Psilotales | Christenhusz et al. (2011) | . | ICBN |
| Psiloxylon | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Psilurus | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Psittacanthus | Santalales | Mabberley (2008) | Loranthaceae. | ICBN |
| Psittacella | Psittaciformes | Clements (2007) | . | ICZN |
| Psittacula | Psittaciformes | Clements (2007) | . | ICZN |
| Psittaculirostris | Psittaciformes | Clements (2007) | . | ICZN |
| Psittacus | Psittaciformes | Clements (2007) | . | ICZN |
| Psitteuteles | Psittaciformes | Clements (2007) | . | ICZN |
| Psittinus | Psittaciformes | Clements (2007) | . | ICZN |
| Psittirostra | Passeriformes | Clements (2007) | . | ICZN |
| Psittrichas | Psittaciformes | Clements (2007) | . | ICZN |
| Psomiocarpa | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Psomophis | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Psophia | Gruiformes | Clements (2007) | . | ICZN |
| Psophocarpus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Psophocichla | Passeriformes | Clements (2007) | . | ICZN |
| Psophodes | Passeriformes | Clements (2007) | . | ICZN |
| Psoralea | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Psoralidium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Psorospermium | Ichthyophonida | Mendoza et al. (2002) | . | ICZN |
| Psorospermum | Malpighiales | Mabberley (2008) | Hypericaceae. | ICBN |
| Psorothamnus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Psychine | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Psychodiella | Eugregarinorida | Votýpka et al. (2009) | . | ICZN |
| Psychopsiella | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Psychopsis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Psychotria | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Psychrilyobacter | Fusobacteriales | Zhao et al. (2009) | . | ICNB |
| Psychrobacillus | Bacillales | Krishnamurthi et al. (2010) | . | ICNB |
| Psychrobacter | Pseudomonadales | Garrity et al. (2005) | . | ICNB |
| Psychroflexus | Flavobacteriales | Garrity et al. (2005) | . | ICNB |
| Psychrogeton | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psychromonas | Alteromonadales | Garrity et al. (2005) | . | ICNB |
| Psychrophyton | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Psychroserpens | Flavobacteriales | Garrity et al. (2005) | . | ICNB |
| Psychrosphaera | Alteromonadales | Park et al. (2010) | . | ICNB |
| Psydrax | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Psygmorchis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Psylliostachys | Caryophyllales | Mabberley (2008) | Plumbaginaceae. | ICBN |
| Psyllocarpus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Ptaeroxylon | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Ptelea | Sapindales | Mabberley (2008) | Rutaceae. | ICBN |
| Pteleocarpa | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pteleopsis | Myrtales | Mabberley (2008) | Combretaceae. | ICBN |
| Ptelidium | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Ptenochirus | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Ptenopus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Pterachaenia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pteralopex | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Pteralyxia | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pterandra | Malpighiales | Mabberley (2008) | Malpighiaceae. | ICBN |
| Pteranthus | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pterichis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pteridium | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pteridoblechnum | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pteridocalyx | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pteridomonas | Pedinellales | Moestrup (2000); Sekiguchi et al. (2003) | . | ICBN |
| Pteridopathes | Antipatharia | Opresko (2004) | . | ICZN |
| Pteridophora | Passeriformes | Clements (2007) | . | ICZN |
| Pteridophyllum | Ranunculales | Mabberley (2008) | Papaveraceae. | ICBN |
| Pteridrys | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pterigynandrum | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pteris | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pternandra | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pternopetalum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pterobryella | Hypnodendrales | Goffinet et al. (2009) | . | ICBN |
| Pterobryidium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pterobryon | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pterobryopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pterocactus | Caryophyllales | Mabberley (2008) | Cactaceae. | ICBN |
| Pterocanium | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Pterocarpus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pterocarya | Fagales | Mabberley (2008) | Juglandaceae. | ICBN |
| Pterocaulon | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pterocelastrus | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Pteroceltis | Rosales | Mabberley (2008) | Cannabaceae. | ICBN |
| Pterocephalidium | Dipsacales | Mabberley (2008) | Caprifoliaceae. | ICBN |
| Pterocephalus | Dipsacales | Mabberley (2008) | Caprifoliaceae. | ICBN |
| Pteroceras | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pterochaeta | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pterochona | Cryptogemmida | Lynn (2008) | . | ICZN |
| Pterochondria | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pterocissus | Vitales | Mabberley (2008) | Vitaceae. | ICBN |
| Pterocladia | Gelidiales | Schneider & Wynne (2007) | . | ICBN |
| Pterocladiella | Gelidiales | Schneider & Wynne (2007) | . | ICBN |
| Pterocladiophila | Gracilariales | Schneider & Wynne (2007) | . | ICBN |
| Pterocladiopsis | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pteroclava | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pterocles | Pterocliformes | Clements (2007) | . | ICZN |
| Pterocorys | Nassellaria | Anderson et al. (2000) | . | ICZN |
| Pterocyclus | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pterocymbium | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pterocypsela | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pterocystis | | Fensome et al. (1993) | Domain Eucarya - Phylum Dinozoa - Superclass Dinokaryota. | ICBN |
| Pterocystis | Pterocystida | Mikrjukov et al. (2000); Cavalier-Smith & von der Heyden (2007); Yabuki et al. (2012) | Pterocystidae. | ICZN |
| Pterodiniella | Entodiniomorphida | Lynn (2008) | . | ICZN |
| Pterodiscus | Lamiales | Mabberley (2008) | Pedaliaceae. | ICBN |
| Pterodon | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pterodroma | Procellariiformes | Clements (2007) | . | ICZN |
| Pteroeides | Pennatulacea | Williams (1995) | . | ICZN |
| Pterogastra | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pteroglossa | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pteroglossaspis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pteroglossus | Piciformes | Clements (2007) | . | ICZN |
| Pterognathia | Filospermoidea | Sørensen (2002) | . | ICZN |
| Pterogonidium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pterogoniopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pterogonium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pterogorgia | Alcyonacea | Bayer (1981) | Gorgoniidae. | ICZN |
| Pterogyne | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pterokrohnia | Aphragmophora | Srinivasan (1986); Bieri (1991) | Absence of transverse muscles (diagnostic characters of Aphragmophora) was reported by (Srinivasan, 1986). Pterokrohniidae. | ICZN |
| Pterolepis | Myrtales | Mabberley (2008) | Melastomataceae. | ICBN |
| Pterolobium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pteromylaeus | Myliobatiformes | Nelson (2006) | . | ICZN |
| Pteromys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pteromyscus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pteronema | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Pteronetta | Anseriformes | Clements (2007) | . | ICZN |
| Pteronia | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pteronotus | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Pteronura | Carnivora | McKenna & Bell (1997) | . | ICZN |
| Pteropepon | Cucurbitales | Mabberley (2008) | Cucurbitaceae. | ICBN |
| Pterophanes | Apodiformes | Clements (2007) | . | ICZN |
| Pteroplatytrygon | Myliobatiformes | Nelson (2006) | . | ICZN |
| Pteropsiella | Jungermanniales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pteroptochos | Passeriformes | Clements (2007) | . | ICZN |
| Pteropus | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Pteropyrum | Caryophyllales | Mabberley (2008) | Polygonaceae. | ICBN |
| Pterorana | Anura | Vitt & Caldwell (2009) | Ranidae. | ICZN |
| Pterorhachis | Sapindales | Mabberley (2008) | Meliaceae. | ICBN |
| Pterosagitta | Aphragmophora | Bieri (1991) | Pterosagittidae. | ICZN |
| Pterosiphonia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pterosperma | Pyramimonadales | Moestrup (2000) | . | ICBN |
| Pterospermum | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pterospora | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pterospora | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pterostegia | Caryophyllales | Mabberley (2008) | Polygonaceae. | ICBN |
| Pterostemma | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pterostemon | Saxifragales | Mabberley (2008) | Iteaceae. | ICBN |
| Pterostenella | Alcyonacea | Bayer (1981) | Primnoidae. | ICZN |
| Pterostylis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pterostyrax | Ericales | Mabberley (2008) | Styracaceae. | ICBN |
| Pterothamnion | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pterozonium | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pteruthius | Passeriformes | Clements (2007) | . | ICZN |
| Pterygascidia | Phlebobranchia | Monniot & Monniot (1972); Kott (2008) | Ciallusiidae. | ICZN |
| Pterygiella | Lamiales | Mabberley (2008) | Orobanchaceae. | ICBN |
| Pterygiosperma | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pterygocalyx | Gentianales | Mabberley (2008) | Gentianaceae. | ICBN |
| Pterygodium | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pterygoneurum | Pottiales | Goffinet et al. (2009) | . | ICBN |
| Pterygopappus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pterygopleurum | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pterygota | Malvales | Mabberley (2008) | Malvaceae. | ICBN |
| Pteryxia | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Ptilagrostis | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Ptilidium | Ptilidiales | Crandall-Stotler et al. (2009) | . | ICBN |
| Ptilimnium | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Ptilinopus | Columbiformes | Clements (2007) | . | ICZN |
| Ptilium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Ptilocaulis | Halichondrida | Alvarez & Hooper (2002) | . | ICZN |
| Ptilocercus | Scandentia | McKenna & Bell (1997) | . | ICZN |
| Ptilochaeta | Malpighiales | Mabberley (2008) | Malpighiaceae. | ICBN |
| Ptilocichla | Passeriformes | Clements (2007) | . | ICZN |
| Ptilocladia | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Ptilocladiopsis | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Ptilocodium | Anthoathecata | Bouillon et al. (2006) | . | ICZN |
| Ptilogonys | Passeriformes | Clements (2007) | . | ICZN |
| Ptilonia | Bonnemaisoniales | Schneider & Wynne (2007) | . | ICBN |
| Ptilonorhynchus | Passeriformes | Clements (2007) | . | ICZN |
| Ptilopachus | Galliformes | Clements (2007) | . | ICZN |
| Ptilophora | Gelidiales | Schneider & Wynne (2007) | . | ICBN |
| Ptiloprora | Passeriformes | Clements (2007) | . | ICZN |
| Ptilopsis | Strigiformes | Clements (2007) | . | ICZN |
| Ptiloris | Passeriformes | Clements (2007) | . | ICZN |
| Ptilorrhoa | Passeriformes | Clements (2007) | . | ICZN |
| Ptilosarcus | Pennatulacea | Williams (1995) | . | ICZN |
| Ptilostemon | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Ptilostomus | Passeriformes | Clements (2007) | . | ICZN |
| Ptilota | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Ptilothamnion | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Ptilothamnionopsis | Ceramiales | Schneider & Wynne (2007); Wynne & Schneider (2010) | . | ICBN |
| Ptilothrix | Poales | Mabberley (2008) | Cyperaceae. | ICBN |
| Ptilotus | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Ptisana | Marattiales | Christenhusz et al. (2011) | . | ICBN |
| Ptyas | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Ptychadena | Anura | Vitt & Caldwell (2009) | Ptychadenidae. | ICZN |
| Ptychanthus | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Ptychococcus | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Ptychocylis | Tintinnida | Lynn (2008) | . | ICZN |
| Ptychodactis | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Ptychodera | Helminthomorpha | Benito (1982) | Ptychoderidae. | ICZN |
| Ptychodiscus | Ptychodiscales | Fensome et al. (1993) | . | ICBN |
| Ptychodium | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Ptychogastria | Trachymedusae | Bouillon et al. (2006) | . | ICZN |
| Ptychogena | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Ptychoglossus | Squamata | Vitt & Caldwell (2009) | Gymnophthalmidae. | ICZN |
| Ptychohyla | Anura | Vitt & Caldwell (2009) | Hylidae. | ICZN |
| Ptycholobium | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Ptychomiliola | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Ptychomitriopsis | Grimmiales | Goffinet et al. (2009) | . | ICBN |
| Ptychomitrium | Grimmiales | Goffinet et al. (2009) | . | ICBN |
| Ptychomniella | Ptychomniales | Goffinet et al. (2009) | . | ICBN |
| Ptychomnion | Ptychomniales | Goffinet et al. (2009) | . | ICBN |
| Ptychopetalum | Santalales | Mabberley (2008) | Olacaceae. | ICBN |
| Ptychophis | Squamata | Mattison (2007); Vitt & Caldwell (2009) | Serpentes. "Colubridae." Not "Ptycophis". | ICZN |
| Ptychopyxis | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Ptychoramphus | Charadriiformes | Clements (2007) | . | ICZN |
| Ptychosema | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Ptychosperma | Arecales | Mabberley (2008) | Palmae. | ICBN |
| Ptychostoma | Trichomonadida | Brugerolle & Lee (2000) | Possibly later synonym of Cochlosoma. | ICZN |
| Ptychostomella | Macrodasyida | Hummon & Todaro (2010) | . | ICZN |
| Ptychostomum | Thigmotrichida | Lynn (2008) | . | ICZN |
| Ptychostomum | Bryales | Goffinet et al. (2009) | . | ICBN |
| Ptychotis | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Ptychozoon | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Ptyctolaemus | Squamata | Vitt & Caldwell (2009) | Agamidae. | ICZN |
| Ptygura | Flosculariaceae | Segers (2002); Segers (2007) | . | ICZN |
| Ptyodactylus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Ptyonoprogne | Passeriformes | Clements (2007) | . | ICZN |
| Ptyrticus | Passeriformes | Clements (2007) | . | ICZN |
| Ptyssiglottis | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Ptyssostoma | Philasterida | Lynn (2008) | . | ICZN |
| Pubistylus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Puccinellia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Puccionia | Brassicales | Mabberley (2008) | Cleomaceae. | ICBN |
| Pucrasia | Galliformes | Clements (2007) | . | ICZN |
| Pudu | Cetartiodactyla | McKenna & Bell (1997); Murphy et al. (2001) | Artiodactyla. | ICZN |
| Puelia | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pueraria | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Puffinus | Procellariiformes | Clements (2007) | . | ICZN |
| Pugetia | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Pugionium | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Puiggariopsis | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pulchranthus | Lamiales | Mabberley (2008) | Acanthaceae. | ICBN |
| Pulchrinodus | Bryales | Goffinet et al. (2009) | . | ICBN |
| Pulicaria | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pulicispora | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Pullea | Oxalidales | Mabberley (2008) | Cunoniaceae. | ICBN |
| Pullenia | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nonionidae. | ICZN |
| Pulleniatina | Globigerinida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Pulleniatinidae. | ICZN |
| Pullulanibacillus | Bacillales | Hatayama et al. (2006) | . | ICNB |
| Pulmonaria | Boraginales | Mabberley (2008) | Boraginaceae. | ICBN |
| Pulsatrix | Strigiformes | Clements (2007) | . | ICZN |
| Pultenaea | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pulvinaria | Sarcinochrysidales | Andersen & Preisig (2000) | Later homonym. Replaced by Chrysoreinhardia. | ICBN |
| Pulvinaster | Compsopogonales | Schneider & Wynne (2007) | . | ICBN |
| Pulvinia | Gigartinales | Schneider & Wynne (2007) | . | ICBN |
| Pulvinularia | Nostocales | Hoffmann et al. (2005) | . | ICBN |
| Pulvinus | Compsopogonales | West et al. (2007); Schneider & Wynne (2007) | Nomen nudum. Replaced by Pulvinaster. | ICBN |
| Puma | Carnivora | Wozencraft (2005) | . | ICZN |
| Punica | Myrtales | Mabberley (2008) | Lythraceae. | ICBN |
| Puniceicoccus | Puniceicoccales | Choo et al. (2007) | . | ICNB |
| Punnettia | Reptantia | Gibson (1995) | . | ICZN |
| Punomys | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pupalia | Caryophyllales | Mabberley (2008) | Amaranthaceae. | ICBN |
| Purdiaea | Ericales | Mabberley (2008) | Clethraceae. | ICBN |
| Purpureicephalus | Psittaciformes | Clements (2007) | . | ICZN |
| Purpureofilum | Stylonematales | Schneider & Wynne (2007) | . | ICBN |
| Purpureostemon | Myrtales | Mabberley (2008) | Myrtaceae. | ICBN |
| Purshia | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Pusa | Carnivora | Wozencraft (2005) | . | ICZN |
| Puschkinia | Asparagales | Mabberley (2008) | Asparagaceae. | ICBN |
| Pusillimonas | Burkholderiales | Stolz et al. (2005) | . | ICNB |
| Pusilloburius | Philasterida | Lynn (2008) | . | ICZN |
| Pussylineus | Heteronemertea | Gibson (1995) | . | ICZN |
| Pustula | Albuginales | Kirk et al. (2008) | Albuginaceae. | ICBN |
| Putranjiva | Malpighiales | Mabberley (2008) | Putranjivaceae. | ICBN |
| Putterlickia | Celastrales | Mabberley (2008) | Celastraceae. | ICBN |
| Puya | Poales | Mabberley (2008) | Bromeliaceae. | ICBN |
| Puytoracia | Euglyphida | Santibáñeza et al. (2011) | . | ICZN |
| Puytoraciella | Colpodida | Lynn (2008); Bourland et al. (2011) | . | ICZN |
| Pycnandra | Ericales | Mabberley (2008) | Sapotaceae. | ICBN |
| Pycnanthemum | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pycnanthus | Actiniaria | Fautin et al. (2007) | . | ICZN |
| Pycnanthus | Magnoliales | Mabberley (2008) | Myristicaceae. | ICBN |
| Pycnarrhena | Ranunculales | Mabberley (2008) | Menispermaceae. | ICBN |
| Pycnobotrya | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pycnocephalum | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pycnoclavella | Aplousobranchia | Monniot & Monniot (1972); Kott (1998); Monniot (2001) | Pycnoclavellidae. | ICZN |
| Pycnococcus | Pseudoscourfieldiales | Moestrup (2000); Guillou et al. (2004); Nakayama et al. (2007) | . | ICBN |
| Pycnocoma | Malpighiales | Mabberley (2008) | Euphorbiaceae. | ICBN |
| Pycnocomon | Dipsacales | Mabberley (2008) | Caprifoliaceae. | ICBN |
| Pycnocycla | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pycnolejeunea | Porellales | Crandall-Stotler et al. (2009) | . | ICBN |
| Pycnonia | Proteales | Mabberley (2008) | Proteaceae. | ICBN |
| Pycnonotus | Passeriformes | Clements (2007) | . | ICZN |
| Pycnophyes | Homalorhagida | Higgins (1990) | . | ICZN |
| Pycnophyllopsis | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pycnophyllum | Caryophyllales | Mabberley (2008) | Caryophyllaceae. | ICBN |
| Pycnoplinthopsis | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pycnoplinthus | Brassicales | Mabberley (2008) | Cruciferae. | ICBN |
| Pycnoptilus | Passeriformes | Clements (2007) | . | ICZN |
| Pycnopygius | Passeriformes | Clements (2007) | . | ICZN |
| Pycnorhachis | Gentianales | Mabberley (2008) | Apocynaceae. | ICBN |
| Pycnospatha | Alismatales | Mabberley (2008) | Araceae. | ICBN |
| Pycnosphaera | Gentianales | Mabberley (2008) | Gentianaceae. | ICBN |
| Pycnospora | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pycnostachys | Lamiales | Mabberley (2008) | Labiatae. | ICBN |
| Pycnothamnion | Ceramiales | Schneider & Wynne (2007) | . | ICBN |
| Pycnotheca | Leptothecata | Bouillon et al. (2006) | . | ICZN |
| Pycnothrix | Vestibuliferida | Lynn (2008) | . | ICZN |
| Pycreus | Poales | Mabberley (2008) | Cyperaceae. | ICBN |
| Pygarrhichas | Passeriformes | Clements (2007) | . | ICZN |
| Pygathrix | Primates | McKenna & Bell (1997) | . | ICZN |
| Pygeretmus | Rodentia | McKenna & Bell (1997) | . | ICZN |
| Pygiptila | Passeriformes | Clements (2007) | . | ICZN |
| Pygmaeorchis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pygmaeoseistron | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Lagenidae. | ICZN |
| Pygmaeothamnus | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pygmotheroides | Clevelandellida | Lynn (2008) | . | ICZN |
| Pygoderma | Chiroptera | McKenna & Bell (1997) | . | ICZN |
| Pygomeles | Squamata | Vitt & Caldwell (2009) | Scincidae. | ICZN |
| Pygopus | Squamata | Vitt & Caldwell (2009) | Gekkonidae. | ICZN |
| Pygoscelis | Sphenisciformes | Clements (2007) | . | ICZN |
| Pylaisia | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pylaisiadelpha | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pylaisiobryum | Hypnales | Goffinet et al. (2009) | . | ICBN |
| Pyloderma | Poecilosclerida | Van Soest (2002) | . | ICZN |
| Pylolena | Spumellaria | Anderson et al. (2000) | . | ICZN |
| Pyracantha | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Pyragra | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pyramidanthe | Magnoliales | Mabberley (2008) | Annonaceae. | ICBN |
| Pyramidobacter | Synergistales | Downes et al. (2009) | . | ICNB |
| Pyramidochrysis | Chromulinales | Kristiansen & Preisig (2001) | Chromulinaceae (uniflagellate). | ICBN |
| Pyramidodinium | | Horiguchi & Sukigara (2005) | Domain Eucarya - Kingdom Alveolatobiontes - Phylum Dinozoa - Class Dinophyceae. | ICBN |
| Pyramidoptera | Apiales | Mabberley (2008) | Umbelliferae. | ICBN |
| Pyramidula | Funariales | Goffinet et al. (2009) | . | ICBN |
| Pyramidulina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Nodosariidae. | ICZN |
| Pyramimonas | Pyramimonadales | Moestrup (2000) | . | ICBN |
| Pyranthus | Fabales | Mabberley (2008) | Leguminosae. | ICBN |
| Pyrenacantha | Icacinales | Mabberley (2008) | Icacinaceae. | ICBN |
| Pyrenaria | Ericales | Mabberley (2008) | Theaceae. | ICBN |
| Pyrenestes | Passeriformes | Clements (2007) | . | ICZN |
| Pyrenomonas | Pyrenomonadales | Clay et al. (1999); Kugrens et al. (2000); Novarino (2003) | Later synonym of Rhodomonas (Novarino, 2003 did not accept the synonymy). | ICBN |
| Pyrgo | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Pyrgoella | Miliolida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Hauerinidae. | ICZN |
| Pyrgophyllum | Zingiberales | Mabberley (2008) | Zingiberaceae. | ICBN |
| Pyriglena | Passeriformes | Clements (2007) | . | ICZN |
| Pyrirhynchus | Heteramorphida | Amin & Van Ha (2008) | . | ICZN |
| Pyrobaculum | Thermoproteales | Garrity et al. (2005) | . | ICNB |
| Pyrocephalus | Passeriformes | Clements (2007) | . | ICZN |
| Pyrococcus | Thermococcales | Garrity et al. (2005) | . | ICNB |
| Pyrocystis | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Pyroderus | Passeriformes | Clements (2007) | . | ICZN |
| Pyrodictium | Desulfurococcales | Garrity et al. (2005) | . | ICNB |
| Pyrodinium | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Pyrola | Ericales | Mabberley (2008) | Ericaceae. | ICBN |
| Pyrolirion | Asparagales | Mabberley (2008) | Amaryllidaceae. | ICBN |
| Pyrolobus | Desulfurococcales | Garrity et al. (2005) | . | ICNB |
| Pyrophacus | Gonyaulacales | Fensome et al. (1993) | . | ICBN |
| Pyrophyllon | Erythropeltidales | Schneider & Wynne (2007) | . | ICBN |
| Pyropia | Bangiales | Sutherland et al. (2011) | . | ICBN |
| Pyropiloides | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Cibicididae. | ICZN |
| Pyropilus | Rotaliida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Cymbaloporidae. | ICZN |
| Pyrorchis | Asparagales | Mabberley (2008) | Orchidaceae. | ICBN |
| Pyrosoma | Pyrosomatida | Godeaux (1998) | . | ICZN |
| Pyrosomella | Pyrosomatida | Godeaux (1998) | . | ICZN |
| Pyrostegia | Lamiales | Mabberley (2008) | Bignoniaceae. | ICBN |
| Pyrostephos | Siphonophorae | Bouillon et al. (2006) | . | ICZN |
| Pyrostremma | Pyrosomatida | Godeaux (1998) | . | ICZN |
| Pyrostria | Gentianales | Mabberley (2008) | Rubiaceae. | ICBN |
| Pyrotheca | Microsporida | Canning & Vavra (2000) | . | ICZN |
| Pyrrhanthera | Poales | Mabberley (2008) | Gramineae. | ICBN |
| Pyrrhobryum | Rhizogoniales | Goffinet et al. (2009) | . | ICBN |
| Pyrrhocoma | Passeriformes | Clements (2007) | . | ICZN |
| Pyrrhocorax | Passeriformes | Clements (2007) | . | ICZN |
| Pyrrholaemus | Passeriformes | Clements (2007) | . | ICZN |
| Pyrrhomyias | Passeriformes | Clements (2007) | . | ICZN |
| Pyrrhopappus | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pyrrhoplectes | Passeriformes | Clements (2007) | . | ICZN |
| Pyrrhosorus | Labyrinthulales | Dick (2001); Kirk et al. (2008) | Labyrinthulales. | ICBN |
| Pyrrhotriadinium | Gonyaulacales | Dodge & Lee (2000); Özdikmen (2009); Nakada (2010) | Later synonym of Triadinium. | ICBN |
| Pyrrhula | Passeriformes | Clements (2007) | . | ICZN |
| Pyrrhura | Psittaciformes | Clements (2007) | . | ICZN |
| Pyrrocoma | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pyrroglaux | Strigiformes | Clements (2007) | . | ICZN |
| Pyrrorhiza | Commelinales | Mabberley (2008) | Haemodoraceae. | ICBN |
| Pyrrosia | Polypodiales | Christenhusz et al. (2011) | . | ICBN |
| Pyrsonympha | Oxymonadida | Brugerolle & Lee (2000) | . | ICZN |
| Pyrularia | Santalales | Mabberley (2008) | Santalaceae. | ICBN |
| Pyrulina | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Polymorphinidae. | ICZN |
| Pyrus | Rosales | Mabberley (2008) | Rosaceae. | ICBN |
| Pythiella | | Dick (2001); Kirk et al. (2008) | Domain Eucarya - Kingdom Straminipila - Phylum Oomycota. Lagenaceae. | ICBN |
| Pythiogeton | Pythiales | Dick (2001); Kirk et al. (2008) | Pythiogetonaceae. | ICBN |
| Pythiopsis | Saprolegniales | Dick (2001); Kirk et al. (2008) | Saprolegniaceae. | ICBN |
| Pythium | Pythiales | Dick (2001); Kirk et al. (2008) | Pythiaceae. | ICBN |
| Python | Squamata | Vitt & Caldwell (2009) | Serpentes. Pythonidae. | ICZN |
| Pythonella | Eucoccidiorida | Perkins et al. (2000) | . | ICZN |
| Pythonodipsas | Squamata | Vitt & Caldwell (2009) | Serpentes. "Colubridae". | ICZN |
| Pytilia | Passeriformes | Clements (2007) | . | ICZN |
| Pytine | Lagenida | Loeblich Jr. & Tappan (1988); Loeblich Jr. & Tappan (1992) | Ellipsolagenidae. | ICZN |
| Pytinocarpa | Asterales | Mabberley (2008) | Compositae. | ICBN |
| Pyura | Stolidobranchia | Monniot & Monniot (1972); Monniot (2001) | Pyuridae. | ICZN |
| Pyxicephalus | Anura | Vitt & Caldwell (2009) | Pyxicephalidae. | ICZN |
| Pyxicoccus | Myxococcales | Garrity et al. (2005) | Incorrect spelling of Pyxidicoccus (see Validations list no. 115). | ICNB |
| Pyxicola | Peritrichida | Lynn (2008); Zhan et al. (2009) | . | ICZN |
| Pyxidanthera | Ericales | Mabberley (2008) | Diapensiaceae. | ICBN |
| Pyxidicoccus | Myxococcales | Garrity et al. (2005) | Corrected name of "Pyxicoccus". | ICNB |
| Pyxidicula | Arcellinida | Meisterfeld (2000) | Arcellina -- Arcellidae. | ICZN |
| Pyxinia | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pyxinioides | Eugregarinorida | Perkins et al. (2000) | . | ICZN |
| Pyxis | Testudinata | Vitt & Caldwell (2009) | Testudinidae. | ICZN |