| Accepted Latin Names | Common Name | In Kent? | Type | Kent ref. | Status | Authority | Record No. |
|---|---|---|---|---|---|---|---|
| Pachysandra terminalis | Carpet Box | Yes S1 | A1 | 90--PAC--ter | Ne | Siebold & Zucc. | * |
| Paeonia lactiflora | Chinese Peony | Clement | A3 | 49--1--lac | Pall. | A3 | |
| Paeonia lutea | Yellow Tree-peony | Clement | A3 | 49--1--lut | Franch. | A3 | |
| Paeonia mascula | Peony | Yes | A1 | 49--1--1 | Ne | (L.) Mill. | * |
| Paeonia officinalis | Garden Peony | Yes S1 | A1 | 49--1--off | Ne | L. | * |
| Pancratium maritimum | Sea Daffodil | Yes S1 | A1 | 158--PAN--mar | Ne | L. | * |
| Panicum antidotale | Clement | A3 | 153--PAN--ant | Retz. | A3 | ||
| Panicum buncei | Clement | A3 | 153--PAN--bun | F. Muell. ex Benth. | A3 | ||
| Panicum capillare | Witch-grass | Stace | A2 | 153--PAN--cap | Ca | L. | A2 |
| Panicum coloratum | Clement | A3 | 153--PAN--col | L. | A3 | ||
| Panicum decompositum | Clement | A3 | 153--PAN--dec | R. Br. | A3 | ||
| Panicum dichotomiflorum | Autumn Millet | Stace | A2 | 153--PAN--dic | Ca | Michx. | A2 |
| Panicum effusum | Clement | A3 | 153--PAN--eff | R. Br. | A3 | ||
| Panicum gilvum | Clement | A3 | 153--PAN--gil | Launert | A3 | ||
| Panicum laevinode | Clement | A3 | 153--PAN--lae | Lindl. | A3 | ||
| Panicum maximum | Clement | A3 | 153--PAN--max | Jacq. | A3 | ||
| Panicum miliaceum | Common Millet | Stace | A2 | 153--PAN--mil | Ca | L. | A2 |
| Panicum mitchellii | Clement | A3 | 153--PAN--mit | Benth. | A3 | ||
| Panicum novemnerve | Clement | A3 | 153--PAN--nov | Stapf | A3 | ||
| Panicum obseptum | Clement | A3 | 153--PAN--obs | Trin. ex Nees | A3 | ||
| Panicum queenslandicum | Clement | A3 | 153--PAN--que | Domin | A3 | ||
| Panicum repens | Clement | A3 | 153--PAN--rep | L. | A3 | ||
| Panicum schinzii | Transvaal Millet | Stace | A2 | 153--PAN--sch | Ca | Hack. ex Schinz | A2 |
| Panicum stapfianum | Clement | A3 | 153--PAN--sta | Fourc. | A3 | ||
| Panicum subalbidum | Clement | A3 | 153--PAN--sub | Kunth | A3 | ||
| Panicum subxerophilum | Clement | A3 | 153--PAN--sux | Domin | A3 | ||
| Panicum virgatum | Clement | A3 | 153--PAN--vir | L. | A3 | ||
| Papaver aculeatum | Bristle Poppy | Clement | A3 | 30--1--acu | Thunb. | A3 | |
| Papaver arenarium | Clement | A3 | 30--1--are | M. Bieb. | A3 | ||
| Papaver argemone | Prickly Poppy | Page 63 | A1 | 30--1--7 | Ar | L. | * |
| Papaver atlanticum | Atlas Poppy | Yes | A1 | 30--1--2 | Ne | (Ball) Coss. | * |
| Papaver bivalve | Clement | A3 | 30--1--biv | (DC.) K.-F. Gnther | A3 | ||
| Papaver bivalve subsp. hybridum | Violet Horned-poppy | Clement | A3 | 30--1--biv--a | (L.) Karlsson | A3 | |
| Papaver commutatum | Clement | A3 | 30--1--com | Fisch. & C.A. Mey. | A3 | ||
| Papaver dubium | Page 63 | A1 | 30--1--5 | Ar | L. | * | |
| Papaver dubium subsp. dubium | Long-headed Poppy | Yes | A1 | 30--1--5--a | Ar | * | |
| Papaver dubium subsp. lecoqii | Yellow-juiced Poppy | Yes | A1 | 30--1--5--b | Ar | (Lamotte) Syme | * |
| Papaver glaucum | Tulip Poppy | Clement | A3 | 30--1--gla | Boiss. & Hausskn. | A4 | |
| Papaver hybridum | Rough Poppy | Yes | A1 | 30--1--6 | Ar | L. | * |
| Papaver laevigatum | Clement | A3 | 30--1--lae | M. Bieb. | A3 | ||
| Papaver nudicaule | Iceland Poppy | Clement | A3 | 30--1--nud | L. | A3 | |
| Papaver pavoninum | Peacock Poppy | Clement | A3 | 30--1--pav | B. Mey. | A3 | |
| Papaver pseudoorientale | Oriental Poppy | Yes S1 | A1 | 30--1--1 | Ne | (Fedde) Medw. | * |
| Papaver rhoeas | Common Poppy | Page 63 | A1 | 30--1--4 | Ar | L. | * |
| Papaver rhoeas x dubium = P. x hungaricum | Yes | A1 | 30--1--4 x 5 | Borb s | * | ||
| Papaver somniferum | Opium Poppy | Page 63 | A1 | 30--1--3 | Ar | L. | * |
| Papaver somniferum subsp. setigerum | Yes | A1 | 30--1--3--b | Ne | (DC.) Arcang. | * | |
| Papaver somniferum subsp. somniferum | Yes | A1 | 30--1--3--a | * | |||
| Parapholis filiformis | Clement | A3 | 153--23--fil | (Roth) C.E. Hubb. | A4 | ||
| Parapholis incurva | Curved Hard-grass | Yes | A1 | 153--23--2 | N | (L.) C.E. Hubb. | * |
| Parapholis pycnantha | Clement | A3 | 153--23--pyc | (Hack. ex Druce) C.E. Hubb. | A4 | ||
| Parapholis strigosa | Hard-grass | Page 63 | A1 | 153--23--1 | N | (Dumort.) C.E. Hubb. | * |
| Parasenecio hastata | Clement | A3 | 135--PAR--has | L. | A3 | ||
| Parentucellia latifolia | Clement | A3 | 124--23--lat | (L.) Caruel | A3 | ||
| Parentucellia viscosa | Yellow Bartsia | Yes | A1 | 124--23--1 | N | (L.) Caruel | * |
| Parietaria judaica | Pellitory-of-the-wall | Page 63 | A1 | 36--2--1 | N | L. | * |
| Parietaria officinalis | Eastern Pellitory-of-the-wall | Yes S1 | A1 | 36--2--off | Ne | L. | * |
| Paris quadrifolia | Herb-paris | Page 63 | A1 | 158--17--1 | N | L. | * |
| Parnassia palustris | Grass-of-Parnassus | Page 63 | A1 | 74--10--1 | N | L. | * |
| Paronychia argentea | Clement | A3 | 46--PAR--arg | Lam. | A3 | ||
| Paronychia argyrocoma | Silverling | Clement | A3 | 46--PAR--ary | (Michx.) Nutt. | A3 | |
| Paronychia brasiliana | Brasilian Nailwort | Clement | A3 | 46--PAR--bra | DC. | A3 | |
| Paronychia polygonifolia | Clement | A3 | 46--PAR--pol | (Vill.) DC. | A3 | ||
| Parthenium hysterophorus | Santa-Maria | Clement | A3 | 135--PAT--hys | L. | A3 | |
| Parthenocissus henryana | Chinese Virginia-creeper | Clement | A3 | 93--2--hen | (Hemsl.) Graebn. ex Diels & Gilg | A3 | |
| Parthenocissus inserta | False Virginia-creeper | Yes | A1 | 93--2--2 | Ne | (A. Kern.) Fritsch | * |
| Parthenocissus quinquefolia | Virginia-creeper | Yes | A1 | 93--2--1 | Ne | (L.) Planch. | * |
| Parthenocissus tricuspidata | Boston-ivy | Yes | A1 | 93--2--3 | Ne | (Siebold & Zucc.) Planch. | * |
| Paspalidium gracile | Clement | A3 | 153--PAS--gra | (R. Br.) Hughes | A3 | ||
| Paspalidium jubiflorum | Clement | A3 | 153--PAS--jub | (Trin.) Hughes | A3 | ||
| Paspalum dilatatum | Dallis-grass | Clement | A3 | 153--69--dil | Poir. | A3 | |
| Paspalum distichum | Water Finger-grass | Yes | A1 | 153--69--1 | Ne | L. | * |
| Paspalum racemosum | Clement | A3 | 153--69--rac | Lam. | A3 | ||
| Passiflora caerulea | Blue Passionflower | Clement | A3 | 59A--PAS--cae | L. | A3 | |
| Pastinaca sativa | Wild Parsnip | Page 63 | A1 | 107--40--1 | N | L. | * |
| Pastinaca sativa subsp. sativa | Clement | AT | 107--40--1--a | AT | |||
| Pastinaca sativa subsp. urens | Clement | A3 | 107--40--1--b | (Req. ex Godr.) Celak. | A4 | ||
| Paulownia tomentosa | Foxglove-tree | Yes S1 | A1 | 124--PAU--tom | Ne | (Thunb.) Steudel | * |
| Pavonia urens | Clement | A3 | 53--PAV--ure | Cav. | A4 | ||
| Pedicularis palustris | Marsh Lousewort | Page 63 | A1 | 124--25--1 | N | L. | * |
| Pedicularis sylvatica | Lousewort | Page 63 | A1 | 124--25--2 | N | L. | * |
| Pedicularis sylvatica subsp. hibernica | Yes | A1 | 124--25--2--b | N | D.A. Webb | * | |
| Pedicularis sylvatica subsp. sylvatica | Yes | A1 | 124--25--2--a | * | |||
| Pedilanthus tithymaloides | Devil's-backbone | Clement | A3 | 91--PED--tit | (L.) Poit. | A3 | |
| Pelargonium capitatum | Rose Geranium | Clement | A3 | 103--PEL--cap | (L.) Aiton | A3 | |
| Pelargonium inodorum | Kopata Geranium | Clement | A3 | 103--PEL--ino | Willd. | A3 | |
| Pelargonium tomentosum | Peppermint-scented Geranium | Clement | A3 | 103--PEL--tom | Ne | Jacq. | A3 |
| Pelargonium x hortorum | Zonal Geranium | Clement | A3 | 103--PEL--hor | L.H. Bailey | A3 | |
| Pennisetum alopecuroides | Clement | A3 | 153--PEN--alo | (L.) Spreng. | A3 | ||
| Pennisetum clandestinum | Clement | A3 | 153--PEN--cla | Hochst. ex Chiov. | A3 | ||
| Pennisetum glaucum | Pearl Millet | Clement | A3 | 153--PEN--gla | (L.) R. Br. | A3 | |
| Pennisetum sphacelatum | Clement | A3 | 153--PEN--sph | (Nees) T. Durand & Schinz | A3 | ||
| Pennisetum thunbergii | Clement | A3 | 153--PEN--thu | Kunth | A3 | ||
| Pentaglottis sempervirens | Green Alkanet | Page 63 | A1 | 116--8--1 | Ne | (L.) Tausch ex L.H. Bailey | * |
| Pentaschistis airoides | Clement | A3 | 153--PET--air | (Nees) Stapf | A3 | ||
| Pentaschistis aristifolia | Clement | A3 | 153--PET--ari | Schweick. | A3 | ||
| Pentzia calcarea | Clement | A3 | 135--PEN--cal | Kies | A3 | ||
| Pentzia cooperi | Clement | A3 | 135--PEN--coo | Harv. | A3 | ||
| Pentzia incana | Clement | A3 | 135--PEN--inc | (Thunb.) Kuntze | A3 | ||
| Perezia multiflora | Clement | A3 | 135--PER--mul | (Humb. & Bonpl.) Less. | A3 | ||
| Pericallis hybrida | Cineraria | Yes | A1 | 135--63--1 | Ne | B. Nord. | * |
| Perilla frutescens | Clement | A3 | 118--PER--fru | (L.) Britton | A3 | ||
| Persea americana | Avocado | Clement | A3 | 24--PER--ame | Mill. | A3 | |
| Persicaria affinis | Himalayan Bistort | Clement | A3 | 47--1--aff | (D. Don) Ronse Decr. | A3 | |
| Persicaria alpina | Alpine Knotweed | Yes | A1 | 47--1--1 | Ne | (All.) H. Gross | * |
| Persicaria alpina x weyrichii = P. x fennica | Finnish Knotweed | Yes S3 | A1 | 47--1--1 x 4 | (Reiersen) Stace | * | |
| Persicaria amphibia | Amphibious Bistort | Page 63 | A1 | 47--1--9 | N | (L.) Delarbre | * |
| Persicaria amplexicaulis | Red Bistort | Yes | A1 | 47--1--7 | Ne | (D. Don) Ronse Decr. | * |
| Persicaria arifolia | Halberd-leaved Tear-thumb | Clement | A3 | 47--1--ari | (L.) Haraldson | A4 | |
| Persicaria bistorta | Common Bistort | Page 63 | A1 | 47--1--6 | N | (L.) Samp. | * |
| Persicaria bungeana | Clement | A3 | 47--1--bun | (Turcz.) Nakai | A4 | ||
| Persicaria campanulata | Lesser Knotweed | Yes | A1 | 47--1--2 | Ne | (Hook. f.) Ronse Decr. | * |
| Persicaria capitata | Pink-headed Persicaria | Clement | A1 | 47--1--cap | Ne | (Buch.-Ham. ex D. Don) H. Gross | * |
| Persicaria glabra | Clement | A3 | 47--1--gla | (Willd.) M. G¢mez | A4 | ||
| Persicaria hydropiper | Water-pepper | Page 63 | A1 | 47--1--14 | N | (L.) Delarbre | * |
| Persicaria hydropiper x minor = P. x subglandulosa | Yes | A1 | 47--1--14 x 16 | (Borb s) Soj k | * | ||
| Persicaria hydropiper x mitis = P. x hybrida | Yes | A1 | 47--1--14 x 15 | (Chaub. ex St.-Amans) Soj k | * | ||
| Persicaria lapathifolia | Pale Persicaria | Page 63 | A1 | 47--1--12 | N | (L.) Delarbre | * |
| Persicaria lapathifolia x hydropiper = P. x figertii | Yes | A1 | 47--1--12 x 14 | (Beck) Soj k | * | ||
| Persicaria maculosa | Redshank | Page 63 | A1 | 47--1--11 | N | Gray | * |
| Persicaria maculosa x hydropiper = P. x intercedens | Yes | A1 | 47--1--11 x 14 | (Beck) Soj k | * | ||
| Persicaria maculosa x lapathifolia = P. x pseudolapathum | Yes S1 | A1 | 47--1--11 x 12 | (Schur) D.H. Kent | * | ||
| Persicaria maculosa x minor = P. x brauniana | Yes | A1 | 47--1--11 x 16 | (F.W. Schultz) Soj k | * | ||
| Persicaria maculosa x mitis = P. x condensata | Yes S1 | A1 | 47--1--11 x 15 | (F.W. Schultz) Soj k | * | ||
| Persicaria minor | Small Water-pepper | Yes | A1 | 47--1--16 | N | (Huds.) Opiz | * |
| Persicaria mitis | Tasteless Water-pepper | Yes S1 | A1 | 47--1--15 | N | (Schrank) Assenov | * |
| Persicaria mitis x minor = P. x wilmsii | Yes S1 | A1 | 47--1--15 x 16 | (Beck) Soj k | * | ||
| Persicaria mollis | Soft Knotweed | Yes | A1 | 47--1--5 | Ne | (D. Don) H. Gross | * |
| Persicaria nepalensis | Nepal Persicaria | Yes | A1 | 47--1--10 | Ne | (Meisn.) H. Gross | * |
| Persicaria orientale | Clement | A3 | 47--1--ori | (L.) Vilm. | A4 | ||
| Persicaria pensylvanica | Pinkweed | Yes | A1 | 47--1--13 | Ne | (L.) M. G¢mez | * |
| Persicaria sagittata | American Tear-thumb | Yes | A1 | 47--1--17 | Ne | (L.) H. Gross ex Nakai | * |
| Persicaria senegalensis | Clement | A3 | 47--1--sen | (L.) H. Gross ex Nakai | A4 | ||
| Persicaria vivipara | Alpine Bistort | Page 65 | A1 | 47--1--8 | N | (L.) Ronse Decr. | * |
| Persicaria wallichii | Himalayan Knotweed | Yes | A1 | 47--1--3 | Ne | Greuter & Burdet | * |
| Persicaria weyrichii | Chinese Knotweed | Yes | A1 | 47--1--4 | Ne | (F. Schmidt) Ronse Decr. | * |
| Petasites albus | White Butterbur | Yes | A1 | 135--71--3 | Ne | (L.) Gaertn. | * |
| Petasites fragrans | Winter Heliotrope | Page 65 | A1 | 135--71--4 | Ne | (Vill.) C. Presl | * |
| Petasites hybridus | Butterbur | Page 65 | A1 | 135--71--1 | N | (L.) P. Gaertn., B. Mey. & Scherb. | * |
| Petasites japonicus | Giant Butterbur | Yes | A1 | 135--71--2 | Ne | (Siebold & Zucc.) Maxim. | * |
| Petasites palmatus | Palmate-leaved Butterbur | Clement | A3 | 135--71--pal | (Aiton) A. Gray | A3 | |
| Petrocoptis pyrenaica | Clement | A3 | 46--PET--pyr | (J.P. Bergeret) A. Braun | A3 | ||
| Petrorhagia dubia | Hairy Pink | Yes S2 | A1 | 46--24--dub | Ne | (Raf.) G. L¢pez & Romo | * |
| Petrorhagia nanteuilii | Childing Pink | Yes | A1 | 46--24--1 | N | (Burnat) P.W. Ball & Heywood | * |
| Petrorhagia prolifera | Proliferous Pink | Yes | A1 | 46--24--2 | Ne | (L.) P.W. Ball & Heywood | * |
| Petrorhagia saxifraga | Tunicflower | Yes | A1 | 46--24--3 | Ne | (L.) Link | * |
| Petroselinum crispum | Garden Parsley | Page 65 | A1 | 107--29--1 | Ar | (Mill.) Nyman ex A.W. Hill | * |
| Petroselinum segetum | Corn Parsley | Yes | A1 | 107--29--2 | N | (L.) W.D.J. Koch | * |
| Petunia axillaris x integrifolia = P. x hybrida | Petunia | Stace | A2 | 110--PET--axi x int | Ne | (Hook.) Vilm. | A2 |
| Peucedanum austriacum | Clement | A3 | 107--39--aus | (Jacq.) W.D.J. Koch | A3 | ||
| Peucedanum officinale | Hog's Fennel | Yes | A1 | 107--39--1 | N | L. | * |
| Peucedanum ostruthium | Masterwort | Yes | A1 | 107--39--3 | Ar | (L.) W.D.J. Koch | * |
| Peucedanum palustre | Milk-parsley | Yes | A1 | 107--39--2 | N | (L.) Moench | * |
| Phacelia campanularia | California-bluebell | Clement | A3 | 115--1--cam | A. Gray | A3 | |
| Phacelia ciliata | Clement | A3 | 115--1--cil | Benth. | A3 | ||
| Phacelia circinata | Clement | A3 | 115--1--cir | J. Jacq. | A3 | ||
| Phacelia congesta | Blue-curls | Clement | A3 | 115--1--con | Hook. | A3 | |
| Phacelia crenulata | Clement | A3 | 115--1--cre | Torr. ex S. Watson | A3 | ||
| Phacelia linearis | Linear-leaved Phacelia | Clement | A3 | 115--1--lin | (Pursh) Holz. | A3 | |
| Phacelia parviflora | Small-flowered Phacelia | Clement | A3 | 115--1--par | Pursh | A3 | |
| Phacelia ramosissima | Branching Phacelia | Clement | A3 | 115--1--ram | Douglas ex Lehm. | A3 | |
| Phacelia tanacetifolia | Phacelia | Yes | A1 | 115--1--1 | Ne | Benth. | * |
| Phacelia viscida | Sticky Phacelia | Clement | A3 | 115--1--vis | (Benth. ex Lindl.) Torr. | A3 | |
| Phalaris angusta | Clement | A3 | 153--38--ang | Nees ex Trin. | A3 | ||
| Phalaris aquatica | Bulbous Canary-grass | Yes | A1 | 153--38--2 | Ne | L. | * |
| Phalaris arundinacea | Reed Canary-grass | Page 65 | A1 | 153--38--1 | N | L. | * |
| Phalaris brachystachys | Confused Canary-grass | Stace | A2 | 153--38--bra | Ca | Link | A3 |
| Phalaris canariensis | Canary-grass | Page 65 | A1 | 153--38--3 | Ne | L. | * |
| Phalaris caroliniana | Clement | A3 | 153--38--car | Walter | A3 | ||
| Phalaris coerulescens | Clement | A3 | 153--38--coe | Desf. | A3 | ||
| Phalaris lemmonii | Clement | A3 | 153--38--lem | Vasey | A3 | ||
| Phalaris minor | Lesser Canary-grass | Yes | A1 | 153--38--4 | Ne | Retz. | * |
| Phalaris paradoxa | Awned Canary-grass | Yes | A1 | 153--38--5 | Ne | L. | * |
| Phalaris truncata | Clement | A3 | 153--38--tru | Guss. ex Bertol. | A3 | ||
| Phaseolus coccineus | Runner Bean | Stace | A2 | 77--PHA--coc | Ca | L. | A2 |
| Phaseolus lunatus | Butter Bean | Clement | A3 | 77--PHA--lun | L. | A3 | |
| Phaseolus vulgaris | French Bean | Stace | A2 | 77--PHA--vul | Ca | L. | A2 |
| Phegopteris connectilis | Beech Fern | Page 65 | A1 | 14--2--1 | N | (Michx.) Watt | * |
| Philadelphus coronarius | Mock-orange | Yes | A1 | 71--1--1 | Ne | L. | * |
| Philadelphus coronarius x microphyllus x pubescens = P. x virginalis | Hairy Mock-orange | Yes | A1 | 71--1--1 x mic x pub | Ne | Rehder | * |
| Philadelphus pubescens | Broad-leaved Mock-orange | Clement | A3 | 71--1--pub | Loisel. | A3 | |
| Philadelphus subcanus | Clement | A3 | 71--1--sub | Koehne | A3 | ||
| Phillyrea latifolia | Clement | A3 | 123--PHI--lat | L. | A3 | ||
| Phleum alpinum | Alpine Cat's-tail | Yes | A1 | 153--49--3 | N | L. | * |
| Phleum arenarium | Sand Cat's-tail | Page 65 | A1 | 153--49--5 | N | L. | * |
| Phleum bertolonii | Smaller Cat's-tail | Page 65 | A1 | 153--49--2 | N | DC. | * |
| Phleum echinatum | Clement | A3 | 153--49--ech | Host | A3 | ||
| Phleum exaratum | Clement | A3 | 153--49--exa | Griseb. | A3 | ||
| Phleum hirsutum | Clement | A3 | 153--49--hir | Honck. | A3 | ||
| Phleum paniculatum | Clement | A3 | 153--49--pan | Huds. | A3 | ||
| Phleum phleoides | Purple-stem Cat's-tail | Yes | A1 | 153--49--4 | N | (L.) H. Karst. | * |
| Phleum pratense | Timothy | Page 65 | A1 | 153--49--1 | N | L. | * |
| Phleum pratense agg. | Aggregate | AK | 153--49--- | AK | |||
| Phleum subulatum | Clement | A3 | 153--49--sub | (Savi) Asch. & Graebn. | A4 | ||
| Phlomis fruticosa | Jerusalem Sage | Yes | A1 | 118--7--2 | Ne | L. | * |
| Phlomis russeliana | Turkish Sage | Yes | A1 | 118--7--1 | Ne | (Sims) Benth. | * |
| Phlomis samia | Greek Sage | Clement | A3 | 118--7--sam | L. | A3 | |
| Phlox drummondii | Annual Phlox | Clement | A3 | 114--PHL--dru | Hook. | A3 | |
| Phlox paniculata | Phlox | Yes S1 | A1 | 114--PHL--pan | Ne | L. | * |
| Phlox subulata | Moss Phlox | Clement | A3 | 114--PHL--sub | L. | A3 | |
| Phoenix dactylifera | Date | Clement | A3 | 146A--PHO--dac | L. | A3 | |
| Phormium cookianum | Lesser New Zealand Flax | Yes | A1 | 160--4--2 | Ne | Le Jol. | * |
| Phormium tenax | New Zealand Flax | Yes | A1 | 160--4--1 | Ne | J.R. Forst. & G. Forst. | * |
| Photinia davidiana | Stranvaesia | Yes | A1 | 75--31--1 | Ne | (Decne.) Cardot | * |
| Phragmites australis | Common Reed | Page 65 | A1 | 153--64--1 | N | (Cav.) Trin. ex Steud. | * |
| Phuopsis stylosa | Caucasian Crosswort | Yes | A1 | 130--4--1 | Ne | (Trin.) Benth. & Hook. f. ex B.D. Jacks. | * |
| Phygelius capensis | Cape Figwort | Yes | A1 | 124--3--1 | Ne | E. Mey. ex Benth. | * |
| Phyla nodiflora | Frogfruit | Clement | A3 | 117--PHY--nod | (L.) Greene | A4 | |
| Phyllitis scolopendrium | Hart's-tongue | Page 65 | A1 | 15--1--1 | N | (L.) Newman | * |
| Phyllitis scolopendrium x Asplenium adiantum-nigrum = X Asplenophyllitis jacksonii | Yes | A1 | 15--1 x 2--1 x 1 | Alston | * | ||
| Phyllitis scolopendrium x Asplenium obovatum = X Asplenophyllitis microdon | Yes | A1 | 15--1 x 2--1 x 3 | (T. Moore) Alston | * | ||
| Phyllitis scolopendrium x Asplenium trichomanes = X Asplenophyllitis confluens | Yes | A1 | 15--1 x 2--1 x 5 | (T. Moore ex E.J. Lowe) Alston | * | ||
| Phyllodoce caerulea | Blue Heath | Yes | A1 | 65--5--1 | N | (L.) Bab. | * |
| Phyllostachys aurea | Clement | A3 | 153--PHY--aur | (CarriŠre) C. RiviŠre & RiviŠre | A3 | ||
| Phyllostachys bambusoides | Clement | A3 | 153--PHY--bam | Siebold & Zucc. | A3 | ||
| Phyllostachys flexuosa | Clement | A3 | 153--PHY--fle | (CarriŠre) C. RiviŠre & RiviŠre | A3 | ||
| Phyllostachys nigra | Clement | A3 | 153--PHY--nig | (G. Lodd.) Munro | A3 | ||
| Phyllostachys viridiglaucescens | Clement | A3 | 153--PHY--vir | (CarriŠre) C. RiviŠre & RiviŠre | A3 | ||
| Phymatosorus diversifolius | Kangaroo Fern | Yes | A1 | 11--2--1 | Ne | (Willd.) Pic. Serm. | * |
| Physalis acutifolia | Wright's Ground-cherry | Clement | A3 | 110--6--acu | (Miers) Sandwith | A4 | |
| Physalis alkekengi | Japanese-lantern | Yes | A1 | 110--6--1 | Ne | L. | * |
| Physalis angulata | Cut-leaved Ground-cherry | Clement | A3 | 110--6--ang | L. | A3 | |
| Physalis fendleri | Clement | A3 | 110--6--fen | A. Gray | A3 | ||
| Physalis foetens | Clement | A3 | 110--6--foe | Poir. | A3 | ||
| Physalis ixocarpa | Tomatillo | Stace | A2 | 110--6--ixo | Ca | Brot. ex Hornem. | A2 |
| Physalis minima | Clement | A3 | 110--6--min | L. | A3 | ||
| Physalis pendula | Lance-leaved Ground-cherry | Clement | A3 | 110--6--pen | Rydb. | A3 | |
| Physalis peruviana | Cape-gooseberry | Yes S1 | A1 | 110--6--per | Ne | L. | * |
| Physalis philadelphica | Large-flowered Tomatillo | Clement | A3 | 110--6--phi | Lam. | A3 | |
| Physalis pubescens | Low Ground-cherry | Clement | A3 | 110--6--pub | L. | A3 | |
| Physalis viscosa | Stellate Ground-cherry | Clement | A3 | 110--6--vis | L. | A3 | |
| Physocarpus amurensis | Clement | A3 | 75--2--amu | (Maxim.) Maxim. | A3 | ||
| Physocarpus opulifolius | Ninebark | Yes | A1 | 75--2--1 | Ne | (L.) Maxim. | * |
| Physochlaina orientalis | Clement | A3 | 110--PHY--ori | (M. Bieb.) G. Don | A4 | ||
| Physospermum cornubiense | Bladderseed | Yes | A1 | 107--24--1 | N | (L.) DC. | * |
| Physostegia virginiana | Obedient-plant | Clement | A3 | 118--PHY--vir | (L.) Benth. | A3 | |
| Phyteuma nigrum | Black Rampion | Clement | A3 | 129--5--nig | F.W. Schmidt | A3 | |
| Phyteuma orbiculare | Round-headed Rampion | Yes | A1 | 129--5--2 | N | L. | * |
| Phyteuma scheuchzeri | Oxford Rampion | Yes | A1 | 129--5--3 | Ne | All. | * |
| Phyteuma spicatum | Spiked Rampion | Yes | A1 | 129--5--1 | N | L. | * |
| Phyteuma spicatum subsp. coeruleum | Clement | A3 | 129--5--1--b | Rich. Schulz | A4 | ||
| Phyteuma spicatum subsp. spicatum | Other | AT | 129--5--1--a | AT | |||
| Phytolacca acinosa | Indian Pokeweed | Yes | A1 | 41--1--1 | Ne | Roxb. | * |
| Phytolacca icosandra | Button Pokeweed | Clement | A3 | 41--1--ico | L. | A3 | |
| Phytolacca octandra | Inkweed | Clement | A3 | 41--1--oct | L. | A3 | |
| Phytolacca polyandra | Chinese Pokeweed | Yes S1 | A1 | 41--1--pol | Ne | Batalin | * |
| Picea abies | Norway Spruce | Yes | A1 | 20--4--2 | Ne | (L.) H. Karst. | * |
| Picea asperata | Dragon Spruce | Clement | A3 | 20--4--asp | Mast. | A3 | |
| Picea breweriana | Brewer Spruce | Clement | A3 | 20--4--bre | S. Watson | A3 | |
| Picea engelmannii | Engelmann Spruce | Stace | A2 | 20--4--eng | Ne | Engelm. | A2 |
| Picea glauca | White Spruce | Stace | A2 | 20--4--gla | Ne | (Moench) Voss | A2 |
| Picea glehnii | Sakhalin Spruce | Clement | A3 | 20--4--gle | (F. Schmidt) Mast. | A3 | |
| Picea montigena | Clement | A3 | 20--4--mon | Mast. | A3 | ||
| Picea omorika | Serbian Spruce | Stace | A2 | 20--4--omo | Ne | (Pancic) Purk. | A2 |
| Picea orientalis | Oriental Spruce | Clement | A3 | 20--4--ori | (L.) Link | A3 | |
| Picea polita | Tiger-tail Spruce | Clement | A3 | 20--4--pol | (Siebold & Zucc.) CarriŠre | A3 | |
| Picea pungens | Colorado Spruce | Clement | A3 | 20--4--pun | Engelm. | A3 | |
| Picea sitchensis | Sitka Spruce | Yes | A1 | 20--4--1 | Ne | (Bong.) CarriŠre | * |
| Picea smithiana | Morinda Spruce | Clement | A3 | 20--4--smi | (Wall.) Boiss. | A3 | |
| Picris altissima | Clement | A3 | 135--17--alt | Delile | A3 | ||
| Picris cupuligera | Clement | A3 | 135--17--cup | (Durieu) Walp. | A3 | ||
| Picris echioides | Bristly Oxtongue | Page 65 | A1 | 135--17--1 | Ar | L. | * |
| Picris hieracioides | Hawkweed Oxtongue | Page 65 | A1 | 135--17--2 | N | L. | * |
| Picris hieracioides subsp. hieracioides | Other | AT | 135--17--2--a | AT | |||
| Picris hieracioides subsp. spinulosa | Clement | A3 | 135--17--2--b | (Bertol. ex Guss.) Arcang. | A3 | ||
| Picris pilosa | Clement | A3 | 135--17--pil | Delile | A3 | ||
| Pieris floribunda | Mountain Fetter-bush | Clement | A3 | 65--PIE--flo | (Pursh ex Sims) Benth. & Hook. | A3 | |
| Pieris formosa | Clement | A3 | 65--PIE--for | (Wall.) D. Don | A3 | ||
| Pieris japonica | Clement | A3 | 65--PIE--jap | (Thunb.) D. Don | A3 | ||
| Pilea microphylla | Artillery-plant | Clement | A3 | 36--PIL--mic | (L.) Liebm. | A3 | |
| Pilosella aurantiaca | Fox-and-cubs | Page 65 | A1 | 135--27--6 | Ne | (L.) F.W. Schultz & Sch. Bip. | * |
| Pilosella aurantiaca subsp. aurantiaca | Yes | A1 | 135--27--6--a | * | |||
| Pilosella aurantiaca subsp. carpathicola | Yes | A1 | 135--27--6--b | (N„geli & Peter) Soj k | * | ||
| Pilosella caespitosa | Yellow Fox-and-cubs | Yes | A1 | 135--27--5 | Ne | (Dumort.) P.D. Sell & C. West | * |
| Pilosella caespitosa subsp. colliniformis | Yes | A1 | 135--27--5--a | (Peter) P.D. Sell & C. West | * | ||
| Pilosella caespitosa x lactucella = P. x floribunda | Irish Fox-and-cubs | Yes S1 | A1 | 135--27--5 x lac | Ne | (Wimm. & Grab.) Arv.-Touv. | * |
| Pilosella flagellaris | Shetland Mouse-ear-hawkweed | Yes | A1 | 135--27--3 | (Willd.) P.D. Sell & C. West | * | |
| Pilosella flagellaris subsp. bicapitata | Yes | A1 | 135--27--3--b | N | P.D. Sell & C. West | * | |
| Pilosella flagellaris subsp. flagellaris | Yes | A1 | 135--27--3--a | Ne | * | ||
| Pilosella lactucella | Clement | A3 | 135--27--lac | (Wallr.) P.D. Sell & C. West | A4 | ||
| Pilosella officinarum | Mouse-ear-hawkweed | Page 65 | A1 | 135--27--2 | N | F.W. Schultz & Sch. Bip. | * |
| Pilosella officinarum x aurantiaca = P. x stoloniflora | Yes | A1 | 135--27--2 x 6 | (Waldst. & Kit.) F.W. Schultz & Sch. Bip. | * | ||
| Pilosella peleteriana | Shaggy Mouse-ear-hawkweed | Yes | A1 | 135--27--1 | N | (M‚rat) F.W. Schultz & Sch. Bip. | * |
| Pilosella peleteriana subsp. peleteriana | Yes | A1 | 135--27--1--a | * | |||
| Pilosella peleteriana subsp. subpeleteriana | Yes | A1 | 135--27--1--b | (N„geli & Peter) P.D. Sell | * | ||
| Pilosella peleteriana subsp. tenuiscapa | Yes | A1 | 135--27--1--c | (Pugsley) P.D. Sell & C. West | * | ||
| Pilosella peleteriana x officinarum = P. x longisquama | Yes | A1 | 135--27--1 x 2 | (Peter) Holub | * | ||
| Pilosella praealta | Tall Mouse-ear-hawkweed | Yes | A1 | 135--27--4 | Ne | (Vill. ex Gochnat) F.W. Schultz & Sch. Bip. | * |
| Pilosella praealta subsp. praealta | Yes | A1 | 135--27--4--a | Ne | * | ||
| Pilosella praealta subsp. thaumasia | Yes | A1 | 135--27--4--b | Ne | (Peter) P.D. Sell | * | |
| Pilularia globulifera | Pillwort | Yes | A1 | 9--1--1 | N | L. | * |
| Pimpinella affinis | Clement | A3 | 107--13--aff | Ledeb. | A3 | ||
| Pimpinella anisum | Clement | A3 | 107--13--ani | L. | A3 | ||
| Pimpinella hirtella | Clement | A3 | 107--13--hir | (Hochst.) A. Rich. | A3 | ||
| Pimpinella major | Greater Burnet-saxifrage | Page 65 | A1 | 107--13--1 | N | (L.) Huds. | * |
| Pimpinella saxifraga | Burnet-saxifrage | Page 65 | A1 | 107--13--2 | N | L. | * |
| Pinguicula alpina | Alpine Butterwort | Yes | A1 | 128--1--2 | ?N | L. | * |
| Pinguicula grandiflora | Large-flowered Butterwort | Yes | A1 | 128--1--4 | N | Lam. | * |
| Pinguicula lusitanica | Pale Butterwort | Page 65 | A1 | 128--1--1 | N | L. | * |
| Pinguicula vulgaris | Common Butterwort | Page 65 | A1 | 128--1--3 | N | L. | * |
| Pinguicula vulgaris x grandiflora = P. x scullyi | Yes | A1 | 128--1--3 x 4 | Druce | * | ||
| Pinus ayacahuite | Mexican White-pine | Clement | A3 | 20--7--aya | Ehrend. | A3 | |
| Pinus banksiana | Jack Pine | Clement | A3 | 20--7--ban | Lamb. | A3 | |
| Pinus cembra | Arolla Pine | Clement | A3 | 20--7--cem | L. | A3 | |
| Pinus contorta | Lodgepole Pine | Yes | A1 | 20--7--3 | Ne | Douglas ex Loudon | * |
| Pinus densiflora | Japanese Pine | Clement | A3 | 20--7--den | Siebold & Zucc. | A3 | |
| Pinus mugo | Dwarf Mountain-pine | Stace | A2 | 20--7--mug | Ne | Turra | A2 |
| Pinus muricata | Bishop Pine | Clement | A3 | 20--7--mur | D. Don | A3 | |
| Pinus nigra | Yes | A1 | 20--7--2 | Ne | J.F. Arnold | * | |
| Pinus nigra subsp. laricio | Corsican Pine | Yes | A1 | 20--7--2--b | Maire | * | |
| Pinus nigra subsp. nigra | Austrian Pine | Yes | A1 | 20--7--2--a | * | ||
| Pinus peuce | Macedonian Pine | Yes S2 | A1 | 20--7--peu | Ne | Griseb. | * |
| Pinus pinaster | Maritime Pine | Yes | A1 | 20--7--4 | Ne | Aiton | * |
| Pinus pinea | Stone Pine | Clement | A3 | 20--7--pin | L. | A3 | |
| Pinus ponderosa | Western Yellow-pine | Stace | A2 | 20--7--pon | Ne | Douglas ex Lawson & C. Lawson | A2 |
| Pinus radiata | Monterey Pine | Yes | A1 | 20--7--5 | Ne | D. Don | * |
| Pinus rigida | Northern Pitch-pine | Clement | A3 | 20--7--rig | Mill. | A4 | |
| Pinus strobus | Weymouth Pine | Yes | A1 | 20--7--6 | Ne | L. | * |
| Pinus sylvestris | Scots Pine | Page 67 | A1 | 20--7--1 | Ne | L. | * |
| Pinus thunbergii | Japanese Black-pine | Clement | A3 | 20--7--thu | Parl. | A3 | |
| Pinus wallichiana | Bhutan Pine | Stace | A2 | 20--7--wal | Ne | A.B. Jacks. | A2 |
| Piptochaetium bicolor | Clement | A3 | 153--PIP--bic | (J. Vahl) E. Desv. | A3 | ||
| Piptochaetium montevidense | Clement | A3 | 153--PIP--mon | (Spreng.) Parodi | A3 | ||
| Pistia stratiotes | Water-lettuce | Clement | A3 | 147--PIS--str | L. | A3 | |
| Pistorinia hispanica | Clement | A3 | 73--PIS--his | (L.) DC. | A3 | ||
| Pisum fulvum | Clement | A3 | 77--PIS--ful | Sibth. & Sm. | A3 | ||
| Pisum sativum | Garden Pea | Stace | A2 | 77--PIS--sat | Ca | L. | A2 |
| Pittosporum crassifolium | Karo | Yes | A1 | 70--1--1 | Ne | Banks & Sol. ex A. Cunn. | * |
| Pittosporum ralphii | Clement | A3 | 70--1--ral | Kirk | A4 | ||
| Pittosporum tenuifolium | Kohuhu | Yes | A1 | 70--1--2 | Ne | Gaertn. | * |
| Plagiobothrys australasicus | Clement | A3 | 116--13--aus | (A. DC.) I.M. Johnst. | A3 | ||
| Plagiobothrys campestris | Fulvous Popcorn-flower | Clement | A3 | 116--13--cam | Greene | A3 | |
| Plagiobothrys canescens | Valley Popcorn-flower | Clement | A3 | 116--13--can | Benth. | A3 | |
| Plagiobothrys elachanthus | Hairy Forget-me-not | Clement | A3 | 116--13--ela | (F. Muell.) I.M. Johnst. | A3 | |
| Plagiobothrys procumbens | Clement | A3 | 116--13--pro | (Colla) A. Gray | A3 | ||
| Plagiobothrys scouleri | White Forget-me-not | Yes | A1 | 116--13--1 | Ne | (Hook. & Arn.) I.M. Johnst. | * |
| Plagiobothrys stipitatus | Stipitate Forget-me-not | Clement | A3 | 116--13--sti | (Greene) I.M. Johnst. | A3 | |
| Plantago afra | Glandular Plantain | Stace | A2 | 121--1--afr | Ca | L. | A2 |
| Plantago albicans | Clement | A3 | 121--1--alb | L. | A3 | ||
| Plantago arenaria | Branched Plantain | Yes | A1 | 121--1--6 | Ne | Waldst. & Kit. | * |
| Plantago aristata | Bracted Plantain | Clement | A3 | 121--1--ari | Michx. | A4 | |
| Plantago coronopus | Buck's-horn Plantain | Page 67 | A1 | 121--1--1 | N | L. | * |
| Plantago exigua | Clement | A3 | 121--1--exi | C. Juss. ex Murray | A3 | ||
| Plantago lagopus | Hare's-foot Plantain | Clement | A3 | 121--1--lag | L. | A3 | |
| Plantago lanceolata | Ribwort Plantain | Page 67 | A1 | 121--1--5 | N | L. | * |
| Plantago loeflingii | Clement | A3 | 121--1--loe | L. | A4 | ||
| Plantago major | Greater Plantain | Page 67 | A1 | 121--1--3 | N | L. | * |
| Plantago major subsp. intermedia | Yes | A1 | 121--1--3--b | N | (Gilib.) Lange | * | |
| Plantago major subsp. major | Yes | A1 | 121--1--3--a | * | |||
| Plantago maritima | Sea Plantain | Page 67 | A1 | 121--1--2 | N | L. | * |
| Plantago media | Hoary Plantain | Page 67 | A1 | 121--1--4 | N | L. | * |
| Plantago notata | Clement | A3 | 121--1--not | Lag. | A3 | ||
| Plantago ovata | Blond Plantain | Clement | A3 | 121--1--ova | Forssk. | A3 | |
| Plantago patagonica | Clement | A3 | 121--1--pat | Jacq. | A3 | ||
| Plantago rugelii | Blackseed Plantain | Clement | A3 | 121--1--rug | Decne. | A3 | |
| Plantago sempervirens | Shrubby Plantain | Clement | A3 | 121--1--sem | Crantz | A3 | |
| Plantago tenuiflora | Clement | A3 | 121--1--ten | Waldst. & Kit. | A3 | ||
| Plantago varia | Variable Plantain | Clement | A3 | 121--1--var | R. Br. | A3 | |
| Plantago virginica | Virginian Plantain | Clement | A3 | 121--1--vir | L. | A3 | |
| Platanthera bifolia | Lesser Butterfly-orchid | Page 67 | A1 | 162--13--2 | N | (L.) Rich. | * |
| Platanthera chlorantha | Greater Butterfly-orchid | Page 67 | A1 | 162--13--1 | N | (Custer) Rchb. | * |
| Platanthera chlorantha x bifolia = P. x hybrida | Yes | A1 | 162--13--1 x 2 | Brgger | * | ||
| Platanus occidentalis | American Plane | Clement | A3 | 32--1--occ | L. | A4 | |
| Platanus occidentalis x orientalis = P. x hispanica | London Plane | Yes | A1 | 32--1--occ x ori | Ne | Mill. ex Mnchh. | * |
| Platanus orientalis | Oriental Plane | Clement | A3 | 32--1--ori | L. | A3 | |
| Platycapnos spicata | Clement | A3 | 31--PLA--spi | (L.) Bernh. | A3 | ||
| Platycladus orientalis | Chinese Thuja | Clement | A3 | 21--PLA--ori | (L.) Franco | A3 | |
| Platystemon californicus | Cream-cups | Clement | A3 | 30--PLA--cal | Benth. | A3 | |
| Pleioblastus auricomus | Clement | A3 | 153--2--aur | (Mitford) D.C. McClint. | A3 | ||
| Pleioblastus chino | Maximowicz's Bamboo | Yes S1 | A1 | 153--2--chi | Ne | (Franch. & Sav.) Makino | * |
| Pleioblastus humilis | Clement | A3 | 153--2--hum | (Mitford) Nakai | A4 | ||
| Pleioblastus pygmaeus | Dwarf Bamboo | Yes | A1 | 153--2--1 | Ne | (Miq.) Nakai | * |
| Pleioblastus simonii | Simon's Bamboo | Yes S1 | A1 | 153--2--sim | Ne | (CarriŠre) Nakai | * |
| Poa alpina | Alpine Meadow-grass | Yes | A1 | 153--18--14 | N | L. | * |
| Poa ampla | Clement | A3 | 153--18--amp | Merr. | A4 | ||
| Poa angustifolia | Narrow-leaved Meadow-grass | Page 67 | A1 | 153--18--6 | N | L. | * |
| Poa annua | Annual Meadow-grass | Page 67 | A1 | 153--18--2 | N | L. | * |
| Poa bulbosa | Bulbous Meadow-grass | Yes | A1 | 153--18--13 | N | L. | * |
| Poa chaixii | Broad-leaved Meadow-grass | Yes | A1 | 153--18--7 | Ne | Vill. | * |
| Poa compressa | Flattened Meadow-grass | Page 67 | A1 | 153--18--9 | N | L. | * |
| Poa costiniana | Clement | A3 | 153--18--cos | Vickery | A4 | ||
| Poa flabellata | Tussac-grass | Yes | A1 | 153--18--15 | Ne | (Lam.) Raspail | * |
| Poa flexuosa | Wavy Meadow-grass | Yes | A1 | 153--18--8 | N | Sm. | * |
| Poa flexuosa x alpina = P. x jemtlandica | Swedish Meadow-grass | Yes | A1 | 153--18--8 x 14 | (Almq.) K. Richt. | * | |
| Poa fordeana | Clement | A3 | 153--18--for | F. Muell. | A4 | ||
| Poa glauca | Glaucous Meadow-grass | Yes | A1 | 153--18--11 | N | Vahl | * |
| Poa gunnii | Clement | A3 | 153--18--gun | Vickery | A4 | ||
| Poa humilis | Spreading Meadow-grass | Page 67 | A1 | 153--18--4 | N | Ehrh. ex Hoffm. | * |
| Poa imbecilla | Clement | A3 | 153--18--imb | Spreng. | A4 | ||
| Poa infirma | Early Meadow-grass | Yes | A1 | 153--18--1 | N | Kunth | * |
| Poa labillardierei | Clement | A3 | 153--18--lab | Steud. | A3 | ||
| Poa leptoclada | Clement | A3 | 153--18--lep | Hochst. | A3 | ||
| Poa ligularis | Clement | A3 | 153--18--lig | Nees ex Steud. | A3 | ||
| Poa nemoralis | Wood Meadow-grass | Page 67 | A1 | 153--18--12 | N | L. | * |
| Poa palustris | Swamp Meadow-grass | Yes | A1 | 153--18--10 | Ne | L. | * |
| Poa poiformis | Clement | A3 | 153--18--poi | (Labill.) Druce | A4 | ||
| Poa pratensis | Smooth Meadow-grass | Page 67 | A1 | 153--18--5 | N | L. | * |
| Poa pratensis agg. | Aggregate | AK | 153--18--- | AK | |||
| Poa schimperiana | Clement | A3 | 153--18--sch | Hochst. ex A. Rich. | A3 | ||
| Poa sieberiana | Clement | A3 | 153--18--sie | Spreng. | A3 | ||
| Poa sterilis | Clement | A3 | 153--18--ste | M. Bieb. | A3 | ||
| Poa trivialis | Rough Meadow-grass | Page 67 | A1 | 153--18--3 | N | L. | * |
| Podolepis gracilis | Slender Podolepis | Clement | A3 | 135--POD--gra | (Lehm.) Graham | A3 | |
| Podolepis longipedata | Tall Copper-wire-daisy | Clement | A3 | 135--POD--lon | A. Cunn. ex DC. | A3 | |
| Podophyllum hexandrum | Himalayan May-apple | Clement | A3 | 29--POD--hex | Royle | A3 | |
| Polemonium caeruleum | Jacob's-ladder | Yes | A1 | 114--1--1 | N | L. | * |
| Polemonium caeruleum subsp. caeruleum | Other | AT | 114--1--1--a | AT | |||
| Polemonium caeruleum subsp. himalayanum | Clement | A3 | 114--1--1--b | (Baker) H. Hara | A3 | ||
| Polemonium foliosissimum | Clement | A3 | 114--1--fol | (A. Gray) A. Gray | A3 | ||
| Polemonium pauciflorum | Clement | A3 | 114--1--pau | S. Watson | A3 | ||
| Polycarpon tetraphyllum | Four-leaved Allseed | Yes | A1 | 46--15--1 | ?N | (L.) L. | * |
| Polycnemum arvense | Clement | A3 | 43--POL--arv | L. | A4 | ||
| Polygala amarella | Dwarf Milkwort | Yes | A1 | 95--1--4 | N | Crantz | * |
| Polygala calcarea | Chalk Milkwort | Page 67 | A1 | 95--1--3 | N | F.W. Schultz | * |
| Polygala chamaebuxus | Shrubby Milkwort | Clement | A3 | 95--1--cha | L. | A4 | |
| Polygala serpyllifolia | Heath Milkwort | Page 67 | A1 | 95--1--2 | N | Hos‚ | * |
| Polygala vulgaris | Common Milkwort | Page 67 | A1 | 95--1--1 | N | L. | * |
| Polygala vulgaris subsp. collina | Yes | A1 | 95--1--1--b | (Rchb.) Borb s | * | ||
| Polygala vulgaris subsp. vulgaris | Yes | A1 | 95--1--1--a | * | |||
| Polygala vulgaris x amarella | Yes S1 | A1 | 95--1--1 x 4 | * | |||
| Polygala vulgaris x calcarea | Yes | A1 | 95--1--1 x 3 | * | |||
| Polygonatum biflorum | Clement | A3 | 158--14--bif | (Walter) Elliott | A4 | ||
| Polygonatum multiflorum | Solomon's-seal | Page 67 | A1 | 158--14--1 | N | (L.) All. | * |
| Polygonatum multiflorum agg. | Aggregate | AK | 158--14--- | AK | |||
| Polygonatum multiflorum x odoratum = P. x hybridum | Garden Solomon's-seal | Yes | A1 | 158--14--1 x 2 | Ne | Brgger | * |
| Polygonatum odoratum | Angular Solomon's-seal | Yes | A1 | 158--14--2 | N | (Mill.) Druce | * |
| Polygonatum verticillatum | Whorled Solomon's-seal | Yes | A1 | 158--14--3 | N | (L.) All. | * |
| Polygonum arenarium | Lesser Red-knotgrass | Stace | A2 | 47--4--are | Ca | Waldst. & Kit. | A2 |
| Polygonum arenarium subsp. pulchellum | Stace | A2 | 47--4--are--a | (Loisel.) Thell. | A2 | ||
| Polygonum arenastrum | Equal-leaved Knotgrass | Page 67 | A1 | 47--4--3 | Ar | Boreau | * |
| Polygonum aviculare | Knotgrass | Page 69 | A1 | 47--4--4 | N | L. | * |
| Polygonum bellardii | Clement | A3 | 47--4--bel | Waldst. & Kit. | A4 | ||
| Polygonum boreale | Northern Knotgrass | Yes | A1 | 47--4--5 | N | (Lange) Small | * |
| Polygonum cognatum | Indian Knotgrass | Clement | A3 | 47--4--cog | Meisn. | A3 | |
| Polygonum corrigioloides | Clement | A3 | 47--4--cor | Jaub. & Spach | A3 | ||
| Polygonum equisetiforme | Clement | A3 | 47--4--equ | Sibth. & Sm. | A3 | ||
| Polygonum graminifolium | Clement | A3 | 47--4--gra | Wierzb. ex Heuff. | A3 | ||
| Polygonum maritimum | Sea Knotgrass | Yes | A1 | 47--4--1 | N | L. | * |
| Polygonum oxyspermum | Ray's Knotgrass | Yes | A1 | 47--4--2 | N | C.A. Mey. & Bunge | * |
| Polygonum oxyspermum subsp. oxyspermum | Clement | A3 | 47--4--2--b | A4 | |||
| Polygonum oxyspermum subsp. raii | Yes | A1 | 47--4--2--a | (Bab.) D.A. Webb & Chater | * | ||
| Polygonum patulum | Red-knotgrass | Stace | A2 | 47--4--pat | Ca | M. Bieb. | A2 |
| Polygonum plebejum | Small Knotweed | Clement | A3 | 47--4--ple | R. Br. | A3 | |
| Polygonum rurivagum | Cornfield Knotgrass | Yes | A1 | 47--4--6 | Ar | Jord. ex Boreau | * |
| Polypodium cambricum | Southern Polypody | Yes | A1 | 11--1--3 | N | L. | * |
| Polypodium interjectum | Intermediate Polypody | Page 69 | A1 | 11--1--2 | N | Shivas | * |
| Polypodium interjectum x cambricum = P. x shivasiae | Yes | A1 | 11--1--2 x 3 | Rothm. | * | ||
| Polypodium vulgare | Polypody | Page 69 | A1 | 11--1--1 | N | L. | * |
| Polypodium vulgare x cambricum = P. x font-queri | Yes | A1 | 11--1--1 x 3 | Rothm. | * | ||
| Polypodium vulgare x interjectum = P. x mantoniae | Yes | A1 | 11--1--1 x 2 | N | Rothm. & U. Schneid. | * | |
| Polypogon australis | Clement | A3 | 153--46--aus | Brongn. | A3 | ||
| Polypogon elongatus | Clement | A3 | 153--46--elo | Kunth | A3 | ||
| Polypogon fugax | Clement | A3 | 153--46--fug | Nees ex Steud. | A3 | ||
| Polypogon linearis | Clement | A3 | 153--46--lin | Trin. | A3 | ||
| Polypogon maritimus | Clement | A3 | 153--46--mar | Willd. | A3 | ||
| Polypogon monspeliensis | Annual Beard-grass | Yes | A1 | 153--46--1 | N | (L.) Desf. | * |
| Polypogon viridis | Water Bent | Yes | A1 | 153--46--2 | Ne | (Gouan) Breistr. | * |
| Polystichum aculeatum | Hard Shield-fern | Page 69 | A1 | 17--1--2 | N | (L.) Roth | * |
| Polystichum aculeatum x lonchitis = P. x illyricum | Yes | A1 | 17--1--2 x 3 | (Borb s) Hahne | * | ||
| Polystichum lonchitis | Holly-fern | Yes | A1 | 17--1--3 | N | (L.) Roth | * |
| Polystichum munitum | Western Sword-fern | Yes S1 | A1 | 17--1--mun | Ne | (Kaulf.) C. Presl | * |
| Polystichum setiferum | Soft Shield-fern | Page 69 | A1 | 17--1--1 | N | (Forssk.) T. Moore ex Woyn. | * |
| Polystichum setiferum x aculeatum = P. x bicknellii | Yes | A1 | 17--1--1 x 2 | N | (H. Christ) Hahne | * | |
| Polystichum setiferum x lonchitis = P. x lonchitiforme | Yes | A1 | 17--1--1 x 3 | (Hal csy) Bech. | * | ||
| Polystichum setiferum x munitum = P. x lesliei | Yes S1 | A1 | 17--1--1 x mun | Rumsey & Acock | * | ||
| Poncirus trifoliata | Japanese Bitter-orange | Clement | A3 | 101A--PON--tri | (L.) Raf. | A4 | |
| Pontederia cordata | Pickerelweed | Yes | A1 | 157--1--1 | Ne | L. | * |
| Populus alba | White Poplar | Page 69 | A1 | 61--1--1 | Ne | L. | * |
| Populus alba x tremula = P. x canescens | Grey Poplar | Page 69 | A1 | 61--1--1 x 2 | Ne | (Aiton) Sm. | * |
| Populus balsamifera | Eastern Balsam-poplar | Stace | A2 | 61--1--bal | Ne | L. | A3 |
| Populus balsamifera x deltoides = P. x jackii | Balm-of-Gilead | Yes S1 | A1 | 61--1--bal x del | Ne | Sarg. | * |
| Populus deltoides | Necklace Poplar | Clement | A3 | 61--1--del | W. Bartram ex Marshall | A3 | |
| Populus laurifolia | Laurel-leaved Poplar | Clement | A3 | 61--1--lau | Ledeb. | A3 | |
| Populus maximowiczii | Japanese Balsam-poplar | Clement | A3 | 61--1--max | A. Henry | A3 | |
| Populus nigra | Black-poplar | Yes | A1 | 61--1--3 | L. | * | |
| Populus nigra subsp. betulifolia | Yes | A1 | 61--1--3--a | N | (Pursh) Dippel | * | |
| Populus nigra x balsamifera x deltoides | Yes S1 | A1 | 61--1--3 x bal x del | * | |||
| Populus nigra x deltoides = P. x canadensis | Hybrid Black-poplar | Yes | A1 | 61--1--3 x del | Ne | Moench | * |
| Populus nigra x laurifolia = P. x berolinensis | Berlin Poplar | Yes S1 | A1 | 61--1--3 x lau | Ne | (K. Koch) Dippel | * |
| Populus tremula | Aspen | Page 69 | A1 | 61--1--2 | N | L. | * |
| Populus tremuloides | American Aspen | Clement | A3 | 61--1--tre | Michx. | A4 | |
| Populus trichocarpa | Western Balsam-poplar | Yes | A1 | 61--1--4 | Ne | Torr. & A. Gray ex Hook. | * |
| Populus trichocarpa x balsamifera = P. 'Balsam Spire' | Hybrid Balsam-poplar | Stace | A2 | 61--1--- | A2 | ||
| Populus trichocarpa x deltoides = P. x generosa | Generous Poplar | Stace | A2 | 61--1--del x 4 | Ne | A. Henry | A2 |
| Populus yunnanensis | Yunnan Poplar | Clement | A3 | 61--1--yun | Dode | A3 | |
| Portulaca grandiflora | Rose-moss | Clement | A3 | 45--1--gra | hort., non Hook. | A3 | |
| Portulaca oleracea | Common Purslane | Yes | A1 | 45--1--1 | Ne | L. | * |
| Potamogeton acutifolius | Sharp-leaved Pondweed | Yes | A1 | 142--1--18 | N | Link | * |
| Potamogeton alpinus | Red Pondweed | Yes | A1 | 142--1--7 | N | Balb. | * |
| Potamogeton alpinus x crispus = P. x olivaceus | Graceful Pondweed | Yes | A1 | 142--1--7 x 19 | Baag›e ex G. Fisch. | * | |
| Potamogeton alpinus x perfoliatus = P. x prussicus | Yes | A1 | 142--1--7 x 9 | Hagstr. | * | ||
| Potamogeton alpinus x praelongus = P. x griffithii | Yes | A1 | 142--1--7 x 8 | A. Benn. | * | ||
| Potamogeton berchtoldii | Small Pondweed | Page 69 | A1 | 142--1--15 | N | Fieber | * |
| Potamogeton berchtoldii x acutifolius = P. x sudermanicus | Yes | A1 | 142--1--15 x 18 | Hagstr. | * | ||
| Potamogeton coloratus | Fen Pondweed | Yes | A1 | 142--1--3 | N | Hornem. | * |
| Potamogeton coloratus x berchtoldii = P. x lanceolatus | Yes | A1 | 142--1--3 x 15 | Sm. | * | ||
| Potamogeton coloratus x gramineus = P. x billupsii | Yes | A1 | 142--1--3 x 6 | Fryer | * | ||
| Potamogeton compressus | Grass-wrack Pondweed | Yes | A1 | 142--1--17 | N | L. | * |
| Potamogeton crispus | Curled Pondweed | Page 69 | A1 | 142--1--19 | N | L. | * |
| Potamogeton epihydrus | American Pondweed | Yes | A1 | 142--1--10 | N | Raf. | * |
| Potamogeton filiformis | Slender-leaved Pondweed | Yes | A1 | 142--1--20 | N | Pers. | * |
| Potamogeton filiformis x pectinatus = P. x suecicus | Swedish Pondweed | Yes | A1 | 142--1--20 x 21 | K. Richt. | * | |
| Potamogeton friesii | Flat-stalked Pondweed | Yes | A1 | 142--1--11 | N | Rupr. | * |
| Potamogeton friesii x acutifolius = P. x pseudofriesii | Yes | A1 | 142--1--11 x 18 | Dandy & G. Taylor | * | ||
| Potamogeton friesii x crispus = P. x lintonii | Linton's Pondweed | Yes | A1 | 142--1--11 x 19 | Fryer | * | |
| Potamogeton gramineus | Various-leaved Pondweed | Yes | A1 | 142--1--6 | N | L. | * |
| Potamogeton gramineus x alpinus = P. x nericius | Yes | A1 | 142--1--6 x 7 | Hagstr. | * | ||
| Potamogeton gramineus x perfoliatus = P. x nitens | Bright-leaved Pondweed | Yes | A1 | 142--1--6 x 9 | N | Weber | * |
| Potamogeton lucens | Shining Pondweed | Page 69 | A1 | 142--1--5 | N | L. | * |
| Potamogeton lucens x alpinus = P. x nerviger | Yes | A1 | 142--1--5 x 7 | Wolfg. | * | ||
| Potamogeton lucens x crispus = P. x cadburyae | Yes | A1 | 142--1--5 x 19 | Dandy & G. Taylor | * | ||
| Potamogeton lucens x gramineus = P. x angustifolius | Long-leaved Pondweed | Yes S2 | A1 | 142--1--5 x 6 | N | J. Presl | * |
| Potamogeton lucens x perfoliatus = P. x salicifolius | Willow-leaved Pondweed | Yes | A1 | 142--1--5 x 9 | N | Wolfg. | * |
| Potamogeton natans | Broad-leaved Pondweed | Page 69 | A1 | 142--1--1 | N | L. | * |
| Potamogeton natans x berchtoldii = P. x variifolius | Yes | A1 | 142--1--1 x 15 | Thore | * | ||
| Potamogeton natans x gramineus = P. x sparganiifolius | Ribbon-leaved Pondweed | Yes | A1 | 142--1--1 x 6 | Laest. ex Fr. | * | |
| Potamogeton natans x lucens = P. x fluitans | Yes | A1 | 142--1--1 x 5 | Roth | * | ||
| Potamogeton natans x nodosus = P. x schreberi | Yes S1 | A1 | 142--1--1 x 4 | G. Fisch. | * | ||
| Potamogeton natans x polygonifolius = P. x gessnacensis | Yes | A1 | 142--1--1 x 2 | G. Fisch. | * | ||
| Potamogeton nodosus | Loddon Pondweed | Yes | A1 | 142--1--4 | N | Poir. | * |
| Potamogeton obtusifolius | Blunt-leaved Pondweed | Yes | A1 | 142--1--14 | N | Mert. & W.D.J. Koch | * |
| Potamogeton pectinatus | Fennel Pondweed | Page 69 | A1 | 142--1--21 | N | L. | * |
| Potamogeton pectinatus x vaginatus = P. x bottnicus | Yes S1 | A1 | 142--1--21 x vag | Hagstr. | * | ||
| Potamogeton perfoliatus | Perfoliate Pondweed | Page 69 | A1 | 142--1--9 | N | L. | * |
| Potamogeton perfoliatus x crispus = P. x cooperi | Cooper's Pondweed | Yes | A1 | 142--1--9 x 19 | (Fryer) Fryer | * | |
| Potamogeton polygonifolius | Bog Pondweed | Page 69 | A1 | 142--1--2 | N | Pourr. | * |
| Potamogeton polygonifolius x gramineus = P. x lanceolatifolius | Yes | A1 | 142--1--2 x 6 | (Tiselius) C.D. Preston | * | ||
| Potamogeton praelongus | Long-stalked Pondweed | Yes | A1 | 142--1--8 | N | Wulfen | * |
| Potamogeton praelongus x crispus = P. x undulatus | Yes | A1 | 142--1--8 x 19 | Wolfg. | * | ||
| Potamogeton praelongus x perfoliatus = P. x cognatus | Yes | A1 | 142--1--8 x 9 | Asch. & Graebn. | * | ||
| Potamogeton pusillus | Lesser Pondweed | Yes | A1 | 142--1--13 | N | L. | * |
| Potamogeton pusillus x trichoides = P. x grovesii | Yes | A1 | 142--1--13 x 16 | Dandy & G. Taylor | * | ||
| Potamogeton rutilus | Shetland Pondweed | Yes | A1 | 142--1--12 | N | Wolfg. | * |
| Potamogeton trichoides | Hairlike Pondweed | Yes | A1 | 142--1--16 | N | Cham. & Schltdl. | * |
| Potamogeton trichoides x crispus = P. x bennettii | Yes | A1 | 142--1--16 x 19 | Fryer | * | ||
| Potentilla alba | White Cinquefoil | Clement | A3 | 75--9--alb | L. | A3 | |
| Potentilla alchemilloides | Alchemilla-leaved Cinquefoil | Clement | A3 | 75--9--alc | Lapeyr. | A3 | |
| Potentilla anglica | Trailing Tormentil | Page 69 | A1 | 75--9--14 | N | Laichard. | * |
| Potentilla anglica x reptans = P. x mixta | Hybrid Cinquefoil | Yes | A1 | 75--9--14 x 15 | N | Nolte ex Rchb. | * |
| Potentilla anserina | Silverweed | Page 69 | A1 | 75--9--3 | N | L. | * |
| Potentilla argentea | Hoary Cinquefoil | Page 69 | A1 | 75--9--5 | N | L. | * |
| Potentilla arguta | Tall Cinquefoil | Clement | A3 | 75--9--arg | Pursh | A3 | |
| Potentilla aurea | Clement | A3 | 75--9--aur | L. | A3 | ||
| Potentilla bifurca | Clement | A3 | 75--9--bif | L. | A3 | ||
| Potentilla canadensis | Clement | A3 | 75--9--can | L. | A3 |