| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| POMO14 | Populus monilifera Ait. | Populus deltoides ssp. monilifera | Salicaceae
|
| PONII | Populus nigra L. var. italica Du Roi | Populus nigra | Salicaceae
|
| PONIV2 | Populus nigra L. var. virginiana (Foug.) Castigl. | Populus deltoides ssp. deltoides | Salicaceae
|
| PONI | Populus nigra L. | Lombardy poplar | Salicaceae
|
| POOC5 | Populus occidentalis (Rydb.) Britt. ex Rydb. | Populus deltoides ssp. monilifera | Salicaceae
|
| POPA25 | Populus palmeri Sarg. | Populus deltoides ssp. deltoides | Salicaceae
|
| POPA11 | Populus �parryi Sarg. | | Salicaceae
|
| POPO12 | Populus �polygonifolia Bernard | Populus tremuloides | Salicaceae
|
| PORO4 | Populus �rouleauiana Boivin | | Salicaceae
|
| POSA18 | Populus salicifolia Raf. | Populus angustifolia | Salicaceae
|
| POSAT | Populus sargentii Dode var. texana (Sarg.) Correll | Populus deltoides ssp. monilifera | Salicaceae
|
| POSA8 | Populus sargentii Dode | Populus deltoides ssp. monilifera | Salicaceae
|
| POSE14 | Populus �sennii Boivin | Populus angustifolia | Salicaceae
|
| POSM2 | Populus �smithii Boivin | | Salicaceae
|
| POTAC | Populus tacamahaca P. Mill. var. candicans (Ait.) Stout | Populus balsamifera ssp. balsamifera | Salicaceae
|
| POTAL | Populus tacamahaca P. Mill. var. lanceolata (Marsh.) Farw. | Populus balsamifera ssp. balsamifera | Salicaceae
|
| POTAM2 | Populus tacamahaca P. Mill. var. michauxii (Dode) Farw. | Populus balsamifera ssp. balsamifera | Salicaceae
|
| POTA2 | Populus tacamahaca P. Mill. | Populus balsamifera ssp. balsamifera | Salicaceae
|
| POTE9 | Populus texana Sarg. | Populus deltoides ssp. monilifera | Salicaceae
|
| POTO7 | Populus tomentosa Carr. | Chinese white poplar | Salicaceae
|
| POTRT | Populus tremula L. ssp. tremuloides (Michx.) A.& D. L�ve | Populus tremuloides | Salicaceae
|
| POTR10 | Populus tremula L. | European aspen | Salicaceae
|
| POTRA | Populus tremuloides Michx. var. aurea (Tidestrom) Daniels | Populus tremuloides | Salicaceae
|
| POTRC2 | Populus tremuloides Michx. var. cercidiphylla (Britt.) Sudworth | Populus tremuloides | Salicaceae
|
| POTRI2 | Populus tremuloides Michx. var. intermedia Victorin | Populus tremuloides | Salicaceae
|
| POTRM | Populus tremuloides Michx. var. magnifica Victorin | Populus tremuloides | Salicaceae
|
| POTRR | Populus tremuloides Michx. var. rhomboidea Victorin | Populus tremuloides | Salicaceae
|
| POTRV | Populus tremuloides Michx. var. vancouveriana (Trel.) Sarg. | Populus tremuloides | Salicaceae
|
| POTR5 | Populus tremuloides Michx. | quaking aspen | Salicaceae
|
| POTRH | Populus trichocarpa Torr. & Gray ex Hook. ssp. hastata (Dode) Dode p.p. | Populus balsamifera ssp. trichocarpa | Salicaceae
|
| POTRC | Populus trichocarpa Torr. & Gray ex Hook. var. cupulata S. Wats. | Populus balsamifera ssp. trichocarpa | Salicaceae
|
| POTRH2 | Populus trichocarpa Torr. & Gray ex Hook. var. hastata (Dode) A. Henry p.p. | Populus balsamifera ssp. trichocarpa | Salicaceae
|
| POTRI | Populus trichocarpa Torr. & Gray ex Hook. var. ingrata (Jepson) Jepson | Populus balsamifera ssp. trichocarpa | Salicaceae
|
| POTR15 | Populus trichocarpa Torr. & Gray ex Hook. | Populus balsamifera ssp. trichocarpa | Salicaceae
|
| POTW2 | Populus tweedyi Britt. | Populus angustifolia | Salicaceae
|
| POVA11 | Populus vancouveriana Trel. | Populus tremuloides | Salicaceae
|
| POVIP2 | Populus virginiana Foug. var. pilosa (Sarg.) F.C. Gates | Populus deltoides ssp. deltoides | Salicaceae
|
| POVI13 | Populus virginiana Foug. | Populus deltoides ssp. deltoides | Salicaceae
|
| POWI3 | Populus wislizeni (S. Wats.) Sarg. | Populus deltoides ssp. wislizeni | Salicaceae
|
| POPUL | Populus L. | cottonwood | Salicaceae
|
| POPA19 | Porana paniculata Roxb. | Poranopsis paniculata | Convolvulaceae
|
| POPA10 | Poranopsis paniculata (Roxb.) Roberty | bridal bouquet | Convolvulaceae
|
| PORAN2 | Poranopsis Roberty | poranopsis | Convolvulaceae
|
| POBO9 | Porella bolanderi (Austin) Pearson | | Porellaceae
|
| POCO41 | Porella cordaeana (Huebener) Moore | | Porellaceae
|
| POFA9 | Porella fauriei (Steph.) S. Hatt. | | Porellaceae
|
| POJAA | Porella japonica (Sande Lac.) Mitt. ssp. appalachiana R. M. Schust. | | Porellaceae
|
| POJA4 | Porella japonica (Sande Lac.) Mitt. | | Porellaceae
|
| PONA7 | Porella navicularis (Lehm. & Lindenb.) Lindb. | | Porellaceae
|
| POPI14 | Porella pinnata L. | | Porellaceae
|
| POPL11 | Porella platyphylla (L.) Pfeiff. | | Porellaceae
|
| PORO14 | Porella roellii Steph. | | Porellaceae
|
| POSW2 | Porella swartziana (Weber) Trevis. | | Porellaceae
|
| POVE8 | Porella vernicosa Lindb. | | Porellaceae
|
| POWA4 | Porella wataugensis (Sull.) Underw. | Watauga porella | Porellaceae
|
| POREL | Porella L. | | Porellaceae
|
| POAE2 | Porina aenea (Wallr.) Zahlbr. | Trichothelium aeneum | Trichotheliaceae
|
| POAM15 | Porina amygdalina Mull. Arg. | wart lichen | Trichotheliaceae
|
| POCA41 | Porina carpinea (Pers. ex Ach.) Zahlbr. | Trichothelium aeneum | Trichotheliaceae
|
| POCE9 | Porina cestrensis (Tuck. ex Michener) Mull. Arg. | wart lichen | Trichotheliaceae
|
| POCH9 | Porina chlorotica (Ach.) Mull. Arg. | Trichothelium chloroticum | Trichotheliaceae
|
| POCI6 | Porina cinerea (Pers.) Zahlbr. | Strigula stigmatella | Strigulaceae
|
| POGU2 | Porina guentheri (Flotow) Zahlbr. | Trichothelium guentheri | Trichotheliaceae
|
| POHE8 | Porina heterospora (Fink) R. C. Harris | wart lichen | Trichotheliaceae
|
| POLE15 | Porina lectissima (Fr.) Zahlbr. | wart lichen | Trichotheliaceae
|
| POLE16 | Porina leptalea (Durieu & Mont.) A. L. Sm. | Segestria leptalea | Trichotheliaceae
|
| POLI10 | Porina linearis (Leighto) Zahlbr. | Trichothelium lineare | Trichotheliaceae
|
| POMA35 | Porina mammillosa (Th. Fr.) Vainio | Segestria mammillosa | Trichotheliaceae
|
| PONI7 | Porina nitidula Mull. Arg. | Trichothelium nitidulum | Trichotheliaceae
|
| PONU7 | Porina nucula Ach. | wart lichen | Trichotheliaceae
|
| PONU8 | Porina nuculastrum (Mull. Arg.) R. C. Harris | wart lichen | Trichotheliaceae
|
| POPL8 | Porina plumbaria (Stizenb.) Hasse | Arthopyrenia plumbaria | Arthopyreniaceae
|
| PORH5 | Porina rhaphidosperma Mull. Arg. | wart lichen | Trichotheliaceae
|
| POSA22 | Porina salicina Mull. Arg. | wart lichen | Trichotheliaceae
|
| POSC17 | Porina scabrida R. C. Harris | wart lichen | Trichotheliaceae
|
| POSU17 | Porina subcinerea (Nyl.) Zahlbr. | Polymeridium subcinereum | Trypetheliaceae
|
| POTH7 | Porina thaxteri R. Sant. | Trichothelium thaxteri | Trichotheliaceae
|
| POVI20 | Porina viridiseda (Nyl.) Zahlbr. | Strigula viridiseda | Strigulaceae
|
| PORIN | Porina Mull. Arg. | wart lichen | Trichotheliaceae
|
| POAN17 | Porlieria angustifolia (Engelm.) Gray | Guajacum angustifolium | Zygophyllaceae
|
| POCO32 | Porocyphus coccodes (Flotow) Korber | | Lichinaceae
|
| PODI14 | Porocyphus dispersus E. Dahl | Thelignya lignyota | Lichinaceae
|
| POFU4 | Porocyphus furfurellus (Nyl.) Forss. | Porocyphus coccodes | Lichinaceae
|
| POKE3 | Porocyphus kenmorensis (Holl ex Nyl.) Henssen | | Lichinaceae
|
| POROC | Porocyphus Korber | porocyphus | Lichinaceae
|
| POCA37 | Porophyllum caesium Greene | Porophyllum gracile | Asteraceae
|
| POGR5 | Porophyllum gracile Benth. | slender poreleaf | Asteraceae
|
| POGR6 | Porophyllum greggii Gray | Gregg's poreleaf | Asteraceae
|
| POJU4 | Porophyllum junciforme Greene | Porophyllum gracile | Asteraceae
|
| POLA13 | Porophyllum latifolium Benth. | Porophyllum ruderale ssp. macrocephalum | Asteraceae
|
| POLE9 | Porophyllum leiocarpum (Urban) Rydb. | yerba de peo | Asteraceae
|
| POMAL | Porophyllum macrocephalum DC. var. leiocarpum Urban | Porophyllum leiocarpum | Asteraceae
|
| POMA30 | Porophyllum macrocephalum DC. | Porophyllum ruderale ssp. macrocephalum | Asteraceae
|
| PONO7 | Porophyllum nodosum M.E. Jones | Porophyllum gracile | Asteraceae
|
| POPO20 | Porophyllum porophyllum (L.) Kuntze | Porophyllum ruderale ssp. ruderale | Asteraceae
|
| POPU15 | Porophyllum putidum A. Nels. | Porophyllum gracile | Asteraceae
|
| POPY | Porophyllum pygmaeum Keil & J. Morefield | dwarf poreleaf | Asteraceae
|
| PORUM2 | Porophyllum ruderale (Jacq.) Cass. ssp. macrocephalum (DC.) R.R. Johnson | yerba porosa | Asteraceae
|
| PORUR | Porophyllum ruderale (Jacq.) Cass. ssp. ruderale | yerba porosa | Asteraceae
|
| PORUM | Porophyllum ruderale (Jacq.) Cass. var. macrocephalum (DC.) Cronq. | Porophyllum ruderale ssp. macrocephalum | Asteraceae
|
| PORU6 | Porophyllum ruderale (Jacq.) Cass. | yerba porosa | Asteraceae
|