| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| PICO10 | Piccolia conspersa (Fee) Vainio | | Biatorellaceae
|
| PICCO | Piccolia A. Massal. | piccolia | Biatorellaceae
|
| PIAB | Picea abies (L.) Karst. | Norway spruce | Pinaceae
|
| PIAU2 | Picea australis Small | Picea rubens | Pinaceae
|
| PIBR | Picea breweriana S. Wats. | Brewer spruce | Pinaceae
|
| PICA10 | Picea canadensis (P. Mill.) B.S.P. | Picea glauca | Pinaceae
|
| PIEN | Picea engelmannii Parry ex Engelm. | Engelmann spruce | Pinaceae
|
| PIEX2 | Picea excelsa (Lamb.) Link | Picea abies | Pinaceae
|
| PIGLE | Picea glauca (Moench) Voss ssp. engelmannii (Parry ex Engelm.) T.M.C. Taylor | Picea engelmannii | Pinaceae
|
| PIGLA2 | Picea glauca (Moench) Voss var. albertiana (S. Br.) Sarg. | Picea glauca | Pinaceae
|
| PIGLD | Picea glauca (Moench) Voss var. densata Bailey | Picea glauca | Pinaceae
|
| PIGLE2 | Picea glauca (Moench) Voss var. engelmannii (Parry ex Engelm.) Boivin | Picea engelmannii | Pinaceae
|
| PIGLP2 | Picea glauca (Moench) Voss var. porsildii Raup | Picea glauca | Pinaceae
|
| PIGL | Picea glauca (Moench) Voss | white spruce | Pinaceae
|
| PIGL7 | Picea glehnii (F. Schmidt) Mast. | Sakhalin spruce | Pinaceae
|
| PILU | Picea �lutzii Little | | Pinaceae
|
| PIMA | Picea mariana (P. Mill.) B.S.P. | black spruce | Pinaceae
|
| PIPU | Picea pungens Engelm. | blue spruce | Pinaceae
|
| PIRU | Picea rubens Sarg. | red spruce | Pinaceae
|
| PISI | Picea sitchensis (Bong.) Carr. | Sitka spruce | Pinaceae
|
| PISM | Picea smithiana (Wall.) Boiss. | morinda spruce | Pinaceae
|
| PICEA | Picea A. Dietr. | spruce | Pinaceae
|
| PIMOT | Pickeringia montana Nutt. ex Torr. & Gray ssp. tomentosa (Abrams) Abrams | Pickeringia montana var. tomentosa | Fabaceae
|
| PIMOM | Pickeringia montana Nutt. ex Torr. & Gray var. montana | Montana chaparral pea | Fabaceae
|
| PIMOT2 | Pickeringia montana Nutt. ex Torr. & Gray var. tomentosa (Abrams) I.M. Johnston | Montana chaparral pea | Fabaceae
|
| PIMO5 | Pickeringia montana Nutt. ex Torr. & Gray | Montana chaparral pea | Fabaceae
|
| PICKE | Pickeringia Nutt. ex Torr. & Gray | chaparral pea | Fabaceae
|
| PIHE7 | Picradenia helenioides Rydb. | Hymenoxys helenioides | Asteraceae
|
| PIOD | Picradenia odorata (DC.) Britt. | Hymenoxys odorata | Asteraceae
|
| PIRIF | Picradenia richardsonii Hook. var. floribunda (Gray) W.A. Weber | Hymenoxys richardsonii var. floribunda | Asteraceae
|
| PIRI6 | Picradenia richardsonii Hook. | Hymenoxys richardsonii var. richardsonii | Asteraceae
|
| PIOP | Picradeniopsis oppositifolia (Nutt.) Rydb. ex Britt. | oppositeleaf bahia | Asteraceae
|
| PIWO | Picradeniopsis woodhousei (Gray) Rydb. | Woodhouse's bahia | Asteraceae
|
| PICRA3 | Picradeniopsis Rydb. ex Britt. | bahia | Asteraceae
|
| PIPE | Picramnia pentandra Sw. | Florida bitterbush | Simaroubaceae
|
| PICRA | Picramnia Sw. | bitterbush | Simaroubaceae
|
| PIAN2 | Picrasma antillana (Eggers) Urban | bitter ash | Simaroubaceae
|
| PIEX | Picrasma excelsa (Sw.) Planch. | bitterwood | Simaroubaceae
|
| PIQU3 | Picrasma quassioides (D. Don) Bennett | nigaki | Simaroubaceae
|
| PICRA2 | Picrasma Blume | picrasma | Simaroubaceae
|
| PIEC | Picris echioides L. | bristly oxtongue | Asteraceae
|
| PIHIH | Picris hieracioides L. ssp. hieracioides | hawkweed oxtongue | Asteraceae
|
| PIHIK | Picris hieracioides L. ssp. kamtschatica (Ledeb.) Hult�n | hawkweed oxtongue | Asteraceae
|
| PIHI | Picris hieracioides L. | hawkweed oxtongue | Asteraceae
|
| PIKA4 | Picris kamtschatica Ledeb. | Picris hieracioides ssp. kamtschatica | Asteraceae
|
| PIPA9 | Picris pauciflora Willd. | smallflower oxtongue | Asteraceae
|
| PISP | Picris sprengeriana (L.) Poir. | bitterweed | Asteraceae
|
| PICRI | Picris L. | oxtongue | Asteraceae
|
| PIDE4 | Picrothamnus desertorum Nutt. | bud sagebrush | Asteraceae
|
| PICRO | Picrothamnus Nutt. | bud sagebrush | Asteraceae
|
| PIAC | Pictetia aculeata (Vahl) Urban | fustic | Fabaceae
|
| PICTE | Pictetia DC. | pictetia | Fabaceae
|
| PIFL | Pieris floribunda (Pursh) Benth. & Hook. f. | mountain fetterbush | Ericaceae
|
| PIJA3 | Pieris japonica (Thunb.) D. Don ex G. Don | Japanese pieris | Ericaceae
|
| PIPH | Pieris phillyreifolia (Hook.) DC. | climbing fetterbush | Ericaceae
|
| PIERI | Pieris D. Don | fetterbush | Ericaceae
|
| PIDE2 | Pilea depressa (Sw.) Blume | depressed clearweed | Urticaceae
|
| PIFO | Pilea fontana (Lunell) Rydb. | lesser clearweed | Urticaceae
|
| PIHE | Pilea herniarioides (Sw.) Lindl. | Caribbean clearweed | Urticaceae
|
| PIIN2 | Pilea inaequalis (Juss. ex Poir.) Weddell | West Indian clearweed | Urticaceae
|
| PIIN6 | Pilea involucrata (Sims) Urban | | Urticaceae
|
| PIKR | Pilea krugii Urban | Krug's clearweed | Urticaceae
|
| PILE2 | Pilea leptophylla Urban | Puerto Rico clearweed | Urticaceae
|
| PIMA5 | Pilea margarettiae Britt. | Margarett's clearweed | Urticaceae
|
| PIMIT | Pilea microphylla (L.) Liebm. var. trianthemoides (Sw.) Griseb. | Pilea trianthemoides | Urticaceae
|
| PIMI2 | Pilea microphylla (L.) Liebm. | rockweed | Urticaceae
|
| PIMU3 | Pilea multicaulis Urban | Liquillo Mountain clearweed | Urticaceae
|
| PINU | Pilea nummulariifolia (Sw.) Weddell | creeping charlie | Urticaceae
|
| PIOB | Pilea obtusata Liebm. | Pilea inaequalis | Urticaceae
|
| PIOP2 | Pilea opaca (Lunell) Rydb. | Pilea fontana | Urticaceae
|
| PIPA7 | Pilea parietaria (L.) Blume | verdolaguilla | Urticaceae
|
| PIPEM | Pilea peploides (Gaud.) Hook. & Arn. var. major Hbd. | Pilea peploides | Urticaceae
|
| PIPE5 | Pilea peploides (Gaud.) Hook. & Arn. | Pacific Island clearweed | Urticaceae
|
| PIPUD | Pilea pumila (L.) Gray var. deamii (Lunell) Fern. | Deam's clearweed | Urticaceae
|
| PIPUP | Pilea pumila (L.) Gray var. pumila | Canadian clearweed | Urticaceae
|
| PIPU2 | Pilea pumila (L.) Gray | Canadian clearweed | Urticaceae
|
| PIRE4 | Pilea repens (Sw.) Weddell | Pilea inaequalis | Urticaceae
|
| PIRI3 | Pilea richardii Urban | Richard's clearweed | Urticaceae
|
| PIRI4 | Pilea rivoriae Weddell | | Urticaceae
|
| PISA4 | Pilea sanctae-crucis Liebm. | Virgin Island clearweed | Urticaceae
|
| PISE2 | Pilea semidentata (Juss. ex Poir.) Weddell | cliffside clearweed | Urticaceae
|
| PISE3 | Pilea serpyllifolia (Poir.) Weddell | Pilea trianthemoides | Urticaceae
|
| PITE4 | Pilea tenerrima Miq. | musgo | Urticaceae
|
| PITR4 | Pilea trianthemoides (Sw.) Lindl. | artillery plant | Urticaceae
|
| PIYU2 | Pilea yunquensis (Urban) Britt. & Wilson | mountain clearweed | Urticaceae
|
| PILEA | Pilea Lindl. | clearweed | Urticaceae
|
| PIRI5 | Piloblephis rigida (Bartr. ex Benth.) Raf. | wild pennyroyal | Lamiaceae
|
| PILOB | Piloblephis Raf. | piloblephis | Lamiaceae
|
| PIJA2 | Pilocarpus jaborandi Holmes | jaborandi | Rutaceae
|
| PIRA3 | Pilocarpus racemosus Vahl | aceitillo | Rutaceae
|
| PILOC | Pilocarpus Vahl | pilocarpus | Rutaceae
|
| PIRO8 | Pilocereus robinii Lem. | Pilosocereus robinii var. robinii | Cactaceae
|
| PIST4 | Pilocereus strictus (DC.) Rumpl. | Pilosocereus royenii | Cactaceae
|
| PIAC60 | Pilophorus acicularis (Ach.) Th. Fr. | nail lichen | Stereocaulaceae
|
| PICE60 | Pilophorus cereolus (Ach.) Th. Fr. | nail lichen | Stereocaulaceae
|
| PICL3 | Pilophorus clavatus Th. Fr. | nail lichen | Stereocaulaceae
|
| PIDO3 | Pilophorus dovrensis (Nyl.) Timdal, Hertel & Rambold | nail lichen | Stereocaulaceae
|
| PIFI2 | Pilophorus fibula (Tuck.) Th. Fr. | nail lichen | Stereocaulaceae
|
| PIHA6 | Pilophorus hallii (Tuck.) Vainio | Pilophorus clavatus | Stereocaulaceae
|
| PINI2 | Pilophorus nigricaulis Sato | nail lichen | Stereocaulaceae
|
| PIPA10 | Pilophorus pallidus (TH. Fr.) Timdal | Pilophorus dovrensis | Stereocaulaceae
|