| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| PYSO2 | Pyrrocoma sonchifolia Greene | Pyrrocoma hirta var. sonchifolia | Asteraceae
|
| PYSU | Pyrrocoma subsquarrosa Greene | Pyrrocoma carthamoides var. subsquarrosa | Asteraceae
|
| PYSU2 | Pyrrocoma subviscosa Greene | Pyrrocoma lanceolata var. subviscosa | Asteraceae
|
| PYUNG | Pyrrocoma uniflora (Hook.) Greene var. gossypina (Greene) Kartesz & Gandhi | plantain goldenweed | Asteraceae
|
| PYUNU | Pyrrocoma uniflora (Hook.) Greene var. uniflora | plantain goldenweed | Asteraceae
|
| PYUN2 | Pyrrocoma uniflora (Hook.) Greene | plantain goldenweed | Asteraceae
|
| PYVI6 | Pyrrocoma villosa Rydb. | Pyrrocoma clementis var. villosa | Asteraceae
|
| PYRRO | Pyrrocoma Hook. | goldenweed | Asteraceae
|
| PYPU | Pyrularia pubera Michx. | buffalo nut | Santalaceae
|
| PYRUL | Pyrularia Michx. | pyrularia | Santalaceae
|
| PYAMD | Pyrus americana (Marsh.) DC. var. decora Sarg. | Sorbus decora | Rosaceae
|
| PYAM2 | Pyrus americana (Marsh.) DC. | Sorbus americana | Rosaceae
|
| PYANS | Pyrus angustifolia Ait. var. spinosa (Rehd.) Bailey | Malus angustifolia var. puberula | Rosaceae
|
| PYAN2 | Pyrus angustifolia Ait. | Malus angustifolia var. angustifolia | Rosaceae
|
| PYARA | Pyrus arbutifolia (L.) L. f. var. atropurpurea (Britt.) B.L. Robins. | Photinia floribunda | Rosaceae
|
| PYARG | Pyrus arbutifolia (L.) L. f. var. glabra Cronq. | Photinia pyrifolia | Rosaceae
|
| PYARN | Pyrus arbutifolia (L.) L. f. var. nigra Willd. | Photinia melanocarpa | Rosaceae
|
| PYAR2 | Pyrus arbutifolia (L.) L. f. | Photinia pyrifolia | Rosaceae
|
| PYAR3 | Pyrus �arnoldiana (Rehd.) Bean | Malus arnoldiana | Rosaceae
|
| PYAU | Pyrus aucuparia (L.) Gaertn. | Sorbus aucuparia | Rosaceae
|
| PYBA3 | Pyrus baccata L. | Malus baccata | Rosaceae
|
| PYBR2 | Pyrus bracteata Bailey | Malus coronaria var. coronaria | Rosaceae
|
| PYCA80 | Pyrus calleryana Dcne. | Callery pear | Rosaceae
|
| PYCO | Pyrus communis L. | common pear | Rosaceae
|
| PYCOD | Pyrus coronaria L. var. dasycalyx (Rehd.) Fern. | Malus coronaria var. dasycalyx | Rosaceae
|
| PYCOE | Pyrus coronaria L. var. elongata (Rehd.) Bailey | Malus coronaria var. coronaria | Rosaceae
|
| PYCOL | Pyrus coronaria L. var. lancifolia (Rehd.) Fern. | Malus coronaria var. dasycalyx | Rosaceae
|
| PYCO4 | Pyrus coronaria L. | Malus coronaria var. coronaria | Rosaceae
|
| PYCY2 | Pyrus cydonia L. | Cydonia oblonga | Rosaceae
|
| PYDEG | Pyrus decora (Sarg.) Hyl. var. groenlandica (Schneid.) Fern. | Sorbus groenlandica | Rosaceae
|
| PYDE2 | Pyrus decora (Sarg.) Hyl. | Sorbus decora | Rosaceae
|
| PYFL5 | Pyrus floribunda Lindl. | Photinia floribunda | Rosaceae
|
| PYFU | Pyrus fusca Raf. | Malus fusca | Rosaceae
|
| PYGL | Pyrus glaucescens (Rehd.) Bailey | Malus glaucescens | Rosaceae
|
| PYIOT | Pyrus ioensis (Wood) Bailey var. texana (Rehd.) Bailey | Malus ioensis var. texana | Rosaceae
|
| PYIO | Pyrus ioensis (Wood) Bailey | Malus ioensis var. ioensis | Rosaceae
|
| PYLA2 | Pyrus lancifolia (Rehd.) Bailey | Malus coronaria var. dasycalyx | Rosaceae
|
| PYMA8 | Pyrus �magdeburgensis hort. | Malus magdeburgensis | Rosaceae
|
| PYMA | Pyrus malus L. | Malus sylvestris | Rosaceae
|
| PYME | Pyrus melanocarpa (Michx.) Willd. | Photinia melanocarpa | Rosaceae
|
| PYMI4 | Pyrus microcarpa (Pursh) Spreng. | Sorbus americana | Rosaceae
|
| PYPI3 | Pyrus pinnatifida Ehrh. | Sorbus thuringiaca | Rosaceae
|
| PYPL | Pyrus �platycarpa (Rehd.) Bailey | Malus platycarpa | Rosaceae
|
| PYPR | Pyrus prunifolia Willd. | Malus prunifolia | Rosaceae
|
| PYPU3 | Pyrus pumila (P. Mill.) K. Koch | Malus pumila | Rosaceae
|
| PYPY2 | Pyrus pyrifolia (Burm. f.) Nakai | Chinese pear | Rosaceae
|
| PYRI3 | Pyrus rivularis Dougl. ex Hook. | Malus fusca | Rosaceae
|
| PYSE5 | Pyrus serotina Rehd. | Pyrus pyrifolia | Rosaceae
|
| PYSI | Pyrus sieboldii Regel | Malus sieboldii var. sieboldii | Rosaceae
|
| PYSI2 | Pyrus sitchensis (M. Roemer) Piper | Sorbus sitchensis var. sitchensis | Rosaceae
|
| PYSO | Pyrus �soulardii Bailey | Malus soulardii | Rosaceae
|
| PYUS2 | Pyrus ussuriensis Maxim. | Chinese pear | Rosaceae
|
| PYZU | Pyrus zumi Matsumura | Malus sieboldii var. zumi | Rosaceae
|
| PYRUS | Pyrus L. | pear | Rosaceae
|
| PYBAB | Pyxidanthera barbulata Michx. var. brevifolia (Wells) Ahles | Pyxidanthera brevifolia | Diapensiaceae
|
| PYBA | Pyxidanthera barbulata Michx. | flowering pixiemoss | Diapensiaceae
|
| PYBR | Pyxidanthera brevifolia Wells | littleleaf pixiemoss | Diapensiaceae
|
| PYSP2 | Pyxidanthera spathulata Muhl. | Lepuropetalon spathulatum | Saxifragaceae
|
| PYXID | Pyxidanthera Michx. | pyxidanthera | Diapensiaceae
|
| PYAL3 | Pyxine albovirens (G. Meyer) Aptroot | | Physciaceae
|
| PYBE2 | Pyxine berteriana (Fee) Imshaug | | Physciaceae
|
| PYCA8 | Pyxine caesiopruinosa (Tuck.) Imahsug | | Physciaceae
|
| PYCH2 | Pyxine chrysanthoides Vainio | Pyxine subcinerea | Physciaceae
|
| PYCO13 | Pyxine cocoes (Sw.) Nyl. | | Physciaceae
|
| PYCO14 | Pyxine coralligera Malme | | Physciaceae
|
| PYES | Pyxine eschweileri (Tuck.) Vainio | | Physciaceae
|
| PYFR | Pyxine frostii Tuck. | Dirinaria frostii | Physciaceae
|
| PYME4 | Pyxine meissneri Tuck. | Pyxine berteriana | Physciaceae
|
| PYPE | Pyxine petricola Nyl. | | Physciaceae
|
| PYPI4 | Pyxine picta (Sw.) Tuck. | Dirinaria picta | Physciaceae
|
| PYPR3 | Pyxine pringlei Imshaug | Pyxine petricola | Physciaceae
|
| PYRE | Pyxine retirugella Nyl. | | Physciaceae
|
| PYSO3 | Pyxine sorediata (Ach.) Mont. | | Physciaceae
|
| PYSU6 | Pyxine subcinerea Stirton | | Physciaceae
|
| PYXIN | Pyxine Fr. | pyxine | Physciaceae
|
| QUAZ | Quamasia azurea Heller | Camassia quamash ssp. azurea | Liliaceae
|
| QUHY2 | Quamasia hyacinthina (Raf.) Britt. | Camassia scilloides | Liliaceae
|
| QUWA4 | Quamasia walpolei Piper | Camassia quamash ssp. walpolei | Liliaceae
|
| QUCO8 | Quamoclidion cordifolium Osterhout | Mirabilis multiflora var. multiflora | Nyctaginaceae
|
| QUGR6 | Quamoclidion greenei (S. Wats.) Standl. | Mirabilis greenei | Nyctaginaceae
|
| QULA4 | Quamoclidion laevis (Benth.) Rydb. | Mirabilis californica var. californica | Nyctaginaceae
|
| QUMU6 | Quamoclidion multiflorum Torr. | Mirabilis multiflora var. multiflora | Nyctaginaceae
|
| QUCO9 | Quamoclit coccinea (L.) Moench | Ipomoea coccinea | Convolvulaceae
|
| QUMU7 | Quamoclit multifida Raf. | Ipomoea multifida | Convolvulaceae
|
| QUQU | Quamoclit quamoclit (L.) Britt. | Ipomoea quamoclit | Convolvulaceae
|
| QUVU2 | Quamoclit vulgaris Choisy | Ipomoea quamoclit | Convolvulaceae
|
| QUTU | Quararibea turbinata (Sw.) Poir. | swizzlestick tree | Bombacaceae
|
| QUARA | Quararibea Aubl. | quararibea | Bombacaceae
|
| QUAM | Quassia amara L. | quassia wood | Simaroubaceae
|
| QUEX3 | Quassia excelsa Sw. | Picrasma excelsa | Simaroubaceae
|
| QUASS | Quassia L. | quassia | Simaroubaceae
|
| QUAC2 | Quercus acerifolia (Palmer) Stoynoff & Hess | mapleleaf oak | Fagaceae
|
| QUAC | Quercus acuminata (Michx.) Houba | Quercus muehlenbergii | Fagaceae
|
| QUAC3 | Quercus �acutidens Torr. | | Fagaceae
|
| QUAC80 | Quercus acutissima Carruthers | sawtooth oak | Fagaceae
|
| QUAE | Quercus aegilops of authors | Quercus macrolepis | Fagaceae
|
| QUAGA | Quercus agrifolia N�e var. agrifolia | California live oak | Fagaceae
|
| QUAGO | Quercus agrifolia N�e var. oxyadenia (Torr.) J.T. Howell | coastal live oak | Fagaceae
|
| QUAG | Quercus agrifolia N�e | California live oak | Fagaceae
|
| QUAJ | Quercus ajoensis C.H. Muller | Ajo Mountain scrub oak | Fagaceae
|
| QUALS | Quercus alba L. var. subcaerulea A.L. & M.C. Pickens | Quercus alba | Fagaceae
|