| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| POPUT2 | Polemonium pulcherrimum Hook. ssp. tricolor (Eastw.) Brand | Polemonium californicum | Polemoniaceae
|
| POPUC | Polemonium pulcherrimum Hook. var. calycinum (Eastw.) Brand | Polemonium californicum | Polemoniaceae
|
| POPUD2 | Polemonium pulcherrimum Hook. var. delicatum (Rydb.) Cronq. | Polemonium pulcherrimum ssp. delicatum | Polemoniaceae
|
| POPUL4 | Polemonium pulcherrimum Hook. var. lindleyi (Wherry) J.P. Anders. | Polemonium pulcherrimum ssp. lindleyi | Polemoniaceae
|
| POPUP2 | Polemonium pulcherrimum Hook. var. pilosum (Greenm.) J.F. Davids. | Polemonium pulcherrimum ssp. pulcherrimum | Polemoniaceae
|
| POPU3 | Polemonium pulcherrimum Hook. | Jacob's-ladder | Polemoniaceae
|
| PORER | Polemonium reptans L. var. reptans | Greek valerian | Polemoniaceae
|
| POREV | Polemonium reptans L. var. villosum E.L. Braun | Greek valerian | Polemoniaceae
|
| PORE2 | Polemonium reptans L. | Greek valerian | Polemoniaceae
|
| POSH2 | Polemonium shastense Baker ex Eastw. | Polemonium pulcherrimum ssp. pulcherrimum | Polemoniaceae
|
| POVA5 | Polemonium vanbruntiae Britt. | Vanbrunt's polemonium | Polemoniaceae
|
| POVIG | Polemonium viscosum Nutt. ssp. genuinum Wherry | Polemonium viscosum | Polemoniaceae
|
| POVIL | Polemonium viscosum Nutt. ssp. lemmonii (Brand) Wherry | Polemonium viscosum | Polemoniaceae
|
| POVIM | Polemonium viscosum Nutt. ssp. mellitum (Gray) J.F. Davids. | Polemonium brandegeei | Polemoniaceae
|
| POVI | Polemonium viscosum Nutt. | sticky polemonium | Polemoniaceae
|
| POLEM | Polemonium L. | Jacob's-ladder | Polemoniaceae
|
| POLA14 | Polianthes lata (Shinners) Shinners | Manfreda virginica | Agavaceae
|
| POMA25 | Polianthes maculosa (Hook.) Shinners | Manfreda maculosa | Agavaceae
|
| PORU13 | Polianthes runyonii Shinners | Manfreda longiflora | Agavaceae
|
| POTU4 | Polianthes tuberosa L. | tuberose | Agavaceae
|
| POVA6 | Polianthes variegata (Jacobi) Shinners | Manfreda variegata | Agavaceae
|
| POVI18 | Polianthes virginica (L.) Shinners | Manfreda virginica | Agavaceae
|
| POLIA | Polianthes L. | polianthes | Agavaceae
|
| POGL4 | Poliomintha glabrescens Gray | leafy rosemary-mint | Lamiaceae
|
| POIN3 | Poliomintha incana (Torr.) Gray | frosted mint | Lamiaceae
|
| POMO17 | Poliomintha mollis (Torr.) Gray | Hedeoma mollis | Lamiaceae
|
| POLIO | Poliomintha Gray | rosemary-mint | Lamiaceae
|
| POBR10 | Polyblastia bryophila Lonnr. | | Verrucariaceae
|
| POCR12 | Polyblastia cruenta (Korber) P. James & Swinscow | | Verrucariaceae
|
| POCU13 | Polyblastia cucurbitula J. W. Thomson & B. M. Murray | | Verrucariaceae
|
| POCU12 | Polyblastia cupularis A. Massal. | | Verrucariaceae
|
| POGE6 | Polyblastia gelatinosa (Ach.) Th. Fr. | | Verrucariaceae
|
| POGO2 | Polyblastia gothica Th. Fr. | | Verrucariaceae
|
| POHYM | Polyblastia hyperborea Th. Fr. var. macrospora Lynge | | Verrucariaceae
|
| POHY60 | Polyblastia hyperborea Th. Fr. | | Verrucariaceae
|
| POIN25 | Polyblastia integrascens (Nyl.) Vainio | Polyblastia hyperborea | Verrucariaceae
|
| POIN26 | Polyblastia intercedens (Nyl.) Lonnr. | Polyblastia cupularis | Verrucariaceae
|
| POME12 | Polyblastia melaspora (Taylor) Zahlbr. | | Verrucariaceae
|
| POOB5 | Polyblastia obsoleta Arnold | | Verrucariaceae
|
| POSE60 | Polyblastia sendtneri Krempelh. | | Verrucariaceae
|
| POSE15 | Polyblastia septentrionalis Lynge | | Verrucariaceae
|
| POSO3 | Polyblastia sommerfeltii Lynge | Polyblastia terrestris | Verrucariaceae
|
| POTE12 | Polyblastia terrestris Th. Fr. | | Verrucariaceae
|
| POTH5 | Polyblastia theleodes (Sommerf.) Th. Fr. | | Verrucariaceae
|
| POTR20 | Polyblastia tristicula (Nyl.) Arnold | Agonimia tristicula | Verrucariaceae
|
| POLYB2 | Polyblastia A. Massal. | polyblastia | Verrucariaceae
|
| PODE9 | Polyblastiopsis dealbens Fink | Polymeridium proponens | Trypetheliaceae
|
| PODI13 | Polyblastiopsis dispora (Mull. Arg.) Zahlbr. | Julella dispora | Thelenellaceae
|
| POFA2 | Polyblastiopsis fallaciosa (Arnold) Zahlbr. | Julella fallaciosa | Thelenellaceae
|
| POFA6 | Polyblastiopsis fallax (Nyl.) Fink | Arthopyrenia analepta | Arthopyreniaceae
|
| POFL16 | Polyblastiopsis floridana Fink | Porina nuculastrum | Trichotheliaceae
|
| POGE9 | Polyblastiopsis geminella (Nyl.) R. C. Harris | Julella geminella | Thelenellaceae
|
| POIN27 | Polyblastiopsis inductula (Nyl.) Fink | Thelenella inductula | Thelenellaceae
|
| POLA19 | Polyblastiopsis lactea (A. Massal.) Zahlbr. | Julella lactea | Thelenellaceae
|
| POQU4 | Polyblastiopsis quercicola Brodo | Julella fallaciosa | Thelenellaceae
|
| PORA12 | Polyblastiopsis rappii Zahlbr. | Julella geminella | Thelenellaceae
|
| POSU16 | Polyblastiopsis sublactea (Nyl.) Zahlbr. | Julella vitrispora | Thelenellaceae
|
| POCE | Polybotrya cervina (L.) Kaulfuss | Olfersia cervina | Dryopteridaceae
|
| POCO30 | Polycarpaea corymbosa (L.) Lam. | oldman's cap | Caryophyllaceae
|
| PONE10 | Polycarpaea nebulosa Lakela | Polycarpaea corymbosa | Caryophyllaceae
|
| POLYC3 | Polycarpaea Lam. | polycarpaea | Caryophyllaceae
|
| POAL25 | Polycarpon alsinifolium (Biv.) DC. | Polycarpon tetraphyllum ssp. alsinifolium | Caryophyllaceae
|
| PODE | Polycarpon depressum Nutt. | California manyseed | Caryophyllaceae
|
| POTEA | Polycarpon tetraphyllum (L.) L. ssp. alsinifolium (Biv.) P.W. Ball | fourleaf manyseed | Caryophyllaceae
|
| POTET2 | Polycarpon tetraphyllum (L.) L. ssp. tetraphyllum | fourleaf manyseed | Caryophyllaceae
|
| POTE | Polycarpon tetraphyllum (L.) L. | fourleaf manyseed | Caryophyllaceae
|
| POLYC | Polycarpon L. | manyseed | Caryophyllaceae
|
| POCO40 | Polycaulonia coralloides (Tuck.) Hue | Caloplaca coralloides | Teloschistaceae
|
| POAL18 | Polychidium albociliatum (Desmaz.) Zahlbr. | Leptochidium albociliatum | Placynthiaceae
|
| POCO39 | Polychidium contortum Henssen | | Placynthiaceae
|
| PODE60 | Polychidium dendriscum (Nyl.) Henssen | | Placynthiaceae
|
| POIN28 | Polychidium intricatulum (Nyl.) Henssen | Dendriscocaulon intricatulum | Lobariaceae
|
| POMU11 | Polychidium muscicola (Sw.) Gray | | Placynthiaceae
|
| PORI6 | Polychidium rivale (Tuck.) Fink | Leptogium rivale | Collemataceae
|
| POUM3 | Polychidium umhausense (Auersw.) Henssen | Dendriscocaulon umhausense | Lobariaceae
|
| POLYC5 | Polychidium (Ach.) Gray | polychidium | Placynthiaceae
|
| POARS | Polycnemum arvense L. var. simplex Wallr. | Polycnemum majus | Chenopodiaceae
|
| POMA24 | Polycnemum majus A. Braun | giant needleleaf | Chenopodiaceae
|
| POLYC4 | Polycnemum L. | polycnemum | Chenopodiaceae
|
| POEP4 | Polycoccum epicrassum (H. Olivier) R. Sant. | Polycoccum squamarioides | Dacampiaceae
|
| POGA2 | Polycoccum galligenum Vezda | Polycoccum pulvinatum | Dacampiaceae
|
| POGE7 | Polycoccum gelidarium (Mudd) D. Hawksw. | Roselliniopsis gelidaria | Uncertain Lichen Family
|
| POMI18 | Polycoccum microstictum (Leighton ex Mudd) Arnold | | Dacampiaceae
|
| POPU18 | Polycoccum pulvinatum (Eitner) R. Sant. | | Dacampiaceae
|
| POSP16 | Polycoccum sporastatiae (Anzi) Arnold | | Dacampiaceae
|
| POSQ2 | Polycoccum squamarioides (Mudd) Arnold | | Dacampiaceae
|
| POLYC7 | Polycoccum Sauter ex Krober | polycoccum | Dacampiaceae
|
| POAS | Polycodium ashei Harbison | Vaccinium stamineum | Ericaceae
|
| POCA35 | Polycodium candicans Small | Vaccinium stamineum | Ericaceae
|
| PODE5 | Polycodium depressum Small | Vaccinium stamineum | Ericaceae
|
| POFL8 | Polycodium floridanum (Nutt.) Greene | Vaccinium stamineum | Ericaceae
|
| POLE10 | Polycodium leptosepalum Small | Vaccinium stamineum | Ericaceae
|
| POMA31 | Polycodium macilentum Small | Vaccinium stamineum | Ericaceae
|
| POME5 | Polycodium melanocarpum (C. Mohr) Small | Vaccinium stamineum | Ericaceae
|
| PONE12 | Polycodium neglectum Small | Vaccinium stamineum | Ericaceae
|
| POST8 | Polycodium stamineum (L.) Greene | Vaccinium stamineum | Ericaceae
|
| POFRB | Polyctenium fremontii (S. Wats.) Greene var. bisulcatum (Greene) Rollins | desert combleaf | Brassicaceae
|
| POFRC | Polyctenium fremontii (S. Wats.) Greene var. confertum Rollins | desert combleaf | Brassicaceae
|
| POFRF2 | Polyctenium fremontii (S. Wats.) Greene var. fremontii | Fremont's combleaf | Brassicaceae
|
| POFR | Polyctenium fremontii (S. Wats.) Greene | desert combleaf | Brassicaceae
|
| POWI | Polyctenium williamsiae Rollins | Washoe combleaf | Brassicaceae
|