| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| ARCHI6 | Archidium Brid. | archidium moss | Archidiaceae
|
| ARAL | Archontophoenix alexandrae (F. Muell.) H. Wendl. & Drude | Alexandra palm | Arecaceae
|
| ARCHO2 | Archontophoenix H. Wendl. & Drude | archontophoenix | Arecaceae
|
| ARANC | Arctagrostis angustifolia Nash var. crassispica Bowden | Arctagrostis latifolia ssp. arundinacea | Poaceae
|
| ARAN9 | Arctagrostis angustifolia Nash | Arctagrostis latifolia ssp. arundinacea | Poaceae
|
| ARAR21 | Arctagrostis arundinacea (Trin.) Beal | Arctagrostis latifolia ssp. arundinacea | Poaceae
|
| ARLAA5 | Arctagrostis latifolia (R. Br.) Griseb. ssp. arundinacea (Trin.) Tzvelev | wideleaf polargrass | Poaceae
|
| ARLAL6 | Arctagrostis latifolia (R. Br.) Griseb. ssp. latifolia | wideleaf polargrass | Poaceae
|
| ARLAN | Arctagrostis latifolia (R. Br.) Griseb. ssp. nahanniensis Porsild | Arctagrostis latifolia ssp. latifolia | Poaceae
|
| ARLAA2 | Arctagrostis latifolia (R. Br.) Griseb. var. angustifolia (Nash) Hult�n | Arctagrostis latifolia ssp. arundinacea | Poaceae
|
| ARLAA | Arctagrostis latifolia (R. Br.) Griseb. var. arundinacea (Trin.) Griseb. | Arctagrostis latifolia ssp. arundinacea | Poaceae
|
| ARLAL5 | Arctagrostis latifolia (R. Br.) Griseb. var. longiglumis Polunin | Arctagrostis latifolia ssp. latifolia | Poaceae
|
| ARLA2 | Arctagrostis latifolia (R. Br.) Griseb. | wideleaf polargrass | Poaceae
|
| ARPO | Arctagrostis poaeoides Nash | Arctagrostis latifolia ssp. arundinacea | Poaceae
|
| ARCTA | Arctagrostis Griseb. | polargrass | Poaceae
|
| ARLA3 | Arctium lappa L. | greater burrdock | Asteraceae
|
| ARMIN | Arctium minus Bernh. ssp. nemorosum (Lej. & Court.) Syme | Arctium vulgare | Asteraceae
|
| ARMI2 | Arctium minus Bernh. | lesser burrdock | Asteraceae
|
| ARNE5 | Arctium nemorosum Lej. & Court. | Arctium vulgare | Asteraceae
|
| ARTO | Arctium tomentosum P. Mill. | woolly burrdock | Asteraceae
|
| ARVU2 | Arctium vulgare (Hill) Evans | woodland burrdock | Asteraceae
|
| ARCTI | Arctium L. | burrdock | Asteraceae
|
| ARAN16 | Arctoa anderssonii Wich. | Andersson's arctoa moss | Dicranaceae
|
| ARBL4 | Arctoa blyttii (Schimp.) Loeske | Kiaeria blyttii | Dicranaceae
|
| ARFA7 | Arctoa falcata (Hedw.) Loeske | Kiaeria falcata | Dicranaceae
|
| ARFUA | Arctoa fulvella (Dicks.) Bruch & Schimp. in B.S.G. var. anderssonii (Wich.) Grout | Arctoa anderssonii | Dicranaceae
|
| ARFU70 | Arctoa fulvella (Dicks.) Bruch & Schimp. in B.S.G. | arctoa moss | Dicranaceae
|
| ARHY5 | Arctoa hyperborea (With.) Bruch & Schimp. in B.S.G. | arctoa moss | Dicranaceae
|
| ARST12 | Arctoa starkei (Web. & Mohr) Loeske | Kiaeria starkei | Dicranaceae
|
| ARCTO5 | Arctoa Bruch & Schimp. in B.S.G. | arctoa moss | Dicranaceae
|
| ARAN18 | Arctocetraria andrejevii (Oksner) Karnefelt & Thell | | Parmeliaceae
|
| ARNI2 | Arctocetraria nigricascens (Nyl.) Karnefelt & Thell | | Parmeliaceae
|
| ARCTO10 | Arctocetraria Karnefelt & Thell | arctocetraria | Parmeliaceae
|
| ARCA4 | Arctomecon californica Torr. & Fr�m. | California bearpoppy | Papaveraceae
|
| ARHU3 | Arctomecon humilis Coville | common bearpoppy | Papaveraceae
|
| ARME2 | Arctomecon merriamii Coville | desert bearpoppy | Papaveraceae
|
| ARCTO | Arctomecon Torr. & Fr�m. | bearpoppy | Papaveraceae
|
| ARDE9 | Arctomia delicatula Th. Fr. | | Arctomiaceae
|
| ARIN13 | Arctomia interfixa (Nyl.) Vainio | arctomia lichen | Arctomiaceae
|
| ARCTO7 | Arctomia Th. Fr. | arctomia | Arctomiaceae
|
| ARAL25 | Arctoparmelia aleuritica (Nyl.) Hale | Arctoparmelia centrifuga | Parmeliaceae
|
| ARCE60 | Arctoparmelia centrifuga (L.) Hale | | Parmeliaceae
|
| ARIN60 | Arctoparmelia incurva (Pers.) Hale | | Parmeliaceae
|
| ARSE60 | Arctoparmelia separata (Th. Fr.) Hale | | Parmeliaceae
|
| ARSU12 | Arctoparmelia subcentrifuga (Oksner) Hale | | Parmeliaceae
|
| ARCTO8 | Arctoparmelia Hale | arctoparmelia | Parmeliaceae
|
| ARTH3 | Arctopeltis thuleana Poelt | | Lecanoraceae
|
| ARCTO9 | Arctopeltis Poelt | arctopeltis | Lecanoraceae
|
| ARFU2 | Arctophila fulva (Trin.) Rupr. ex Anderss. | pendantgrass | Poaceae
|
| ARCTO2 | Arctophila Rupr. ex Anderss. | pendantgrass | Poaceae
|
| ARAC | Arctostaphylos acutifolia Eastw. | Arctostaphylos patula | Ericaceae
|
| ARAD3 | Arctostaphylos adenotricha (Fern. & J.F. Macbr.) A.& D. L�ve & Kapoor | Arctostaphylos uva-ursi | Ericaceae
|
| ARALR2 | Arctostaphylos alpina (L.) Spreng. ssp. rubra (Rehd. & Wilson) Hult�n | Arctostaphylos rubra | Ericaceae
|
| ARALR | Arctostaphylos alpina (L.) Spreng. var. rubra (Rehd. & Wilson) Bean | Arctostaphylos rubra | Ericaceae
|
| ARAL2 | Arctostaphylos alpina (L.) Spreng. | alpine bearberry | Ericaceae
|
| ARANI | Arctostaphylos andersonii Gray var. imbricata (Eastw.) J.E. Adams ex McMinn | Arctostaphylos imbricata | Ericaceae
|
| ARANP | Arctostaphylos andersonii Gray var. pallida (Eastw.) J.E. Adams ex McMinn | Arctostaphylos pallida | Ericaceae
|
| ARAN2 | Arctostaphylos andersonii Gray | Santa Cruz manzanita | Ericaceae
|
| ARAU | Arctostaphylos auriculata Eastw. | Mount Diablo manzanita | Ericaceae
|
| ARBAB | Arctostaphylos bakeri Eastw. ssp. bakeri | Baker's manzanita | Ericaceae
|
| ARBAS | Arctostaphylos bakeri Eastw. ssp. sublaevis P.V. Wells | The Cedars manzanita | Ericaceae
|
| ARBA4 | Arctostaphylos bakeri Eastw. | Baker's manzanita | Ericaceae
|
| ARBE3 | Arctostaphylos �benitoensis J.B. Roof (pro sp.) | | Ericaceae
|
| ARBI7 | Arctostaphylos bicolor (Nutt.) Gray | Xylococcus bicolor | Ericaceae
|
| ARBO3 | Arctostaphylos bowermaniae J.B. Roof | Arctostaphylos manzanita ssp. manzanita | Ericaceae
|
| ARBR5 | Arctostaphylos bracteata T.J. Howell | Arctostaphylos cinerea | Ericaceae
|
| ARBRH | Arctostaphylos bracteosa (DC.) Abrams var. hebeclada (DC.) Eastw. | Arctostaphylos tomentosa ssp. bracteosa | Ericaceae
|
| ARBR6 | Arctostaphylos bracteosa (DC.) Abrams | Arctostaphylos tomentosa ssp. bracteosa | Ericaceae
|
| ARCA33 | Arctostaphylos �campbelliae Eastw. (pro sp.) | | Ericaceae
|
| ARCA27 | Arctostaphylos candidissima Eastw. | Arctostaphylos canescens ssp. canescens | Ericaceae
|
| ARCAC7 | Arctostaphylos canescens Eastw. ssp. canescens | hoary manzanita | Ericaceae
|
| ARCAM | Arctostaphylos canescens Eastw. ssp. malloryi W. Knight & Gankin | Arctostaphylos malloryi | Ericaceae
|
| ARCAS3 | Arctostaphylos canescens Eastw. ssp. sonomensis (Eastw.) P.V. Wells | Sonoma manzanita | Ericaceae
|
| ARCAC2 | Arctostaphylos canescens Eastw. var. candidissima (Eastw.) Munz | Arctostaphylos canescens ssp. canescens | Ericaceae
|
| ARCAS | Arctostaphylos canescens Eastw. var. sonomensis (Eastw.) J.E. Adams ex McMinn | Arctostaphylos canescens ssp. sonomensis | Ericaceae
|
| ARCA5 | Arctostaphylos canescens Eastw. | hoary manzanita | Ericaceae
|
| ARCA21 | Arctostaphylos catalinae P.V. Wells | Santa Catalina Island manzanita | Ericaceae
|
| ARCH9 | Arctostaphylos chaloneorum J.B. Roof | Arctostaphylos pungens | Ericaceae
|
| ARCI | Arctostaphylos �cinerea T.J. Howell (pro sp.) | Waldo manzanita | Ericaceae
|
| ARCO23 | Arctostaphylos �coloradensis Rollins (pro sp.) | | Ericaceae
|
| ARCON2 | Arctostaphylos columbiana Piper ssp. nortensis (P.V. Wells) P.V. Wells | Arctostaphylos nortensis | Ericaceae
|
| ARCOT | Arctostaphylos columbiana Piper var. tracyi Eastw. | Arctostaphylos columbiana | Ericaceae
|
| ARCO3 | Arctostaphylos columbiana Piper | hairy manzanita | Ericaceae
|
| ARCO13 | Arctostaphylos confertiflora Eastw. | Santa Rosa Island manzanita | Ericaceae
|
| ARCRR | Arctostaphylos crustacea Eastw. var. rosei (Eastw.) McMinn | Arctostaphylos tomentosa ssp. rosei | Ericaceae
|
| ARCRT | Arctostaphylos crustacea Eastw. var. tomentosiformis J.E. Adams | Arctostaphylos tomentosa ssp. crinita | Ericaceae
|
| ARCR3 | Arctostaphylos crustacea Eastw. | Arctostaphylos tomentosa ssp. crustacea | Ericaceae
|
| ARCR6 | Arctostaphylos cruzensis J.B. Roof | La Cruz manzanita | Ericaceae
|
| ARDE2 | Arctostaphylos densiflora M.S. Baker | Vine Hill manzanita | Ericaceae
|
| ARDI16 | Arctostaphylos diversifolia (Parry) Parry ex Gray | Comarostaphylis diversifolia ssp. diversifolia | Ericaceae
|
| ARDR7 | Arctostaphylos drupacea (Parry) J.F. Macbr. | Arctostaphylos pringlei ssp. drupacea | Ericaceae
|
| AREDP | Arctostaphylos edmundsii J.T. Howell var. parvifolia J.B. Roof | Arctostaphylos edmundsii | Ericaceae
|
| ARED | Arctostaphylos edmundsii J.T. Howell | Little Sur manzanita | Ericaceae
|
| AREL | Arctostaphylos elegans Eastw. | Arctostaphylos manzanita ssp. elegans | Ericaceae
|
| ARFR8 | Arctostaphylos franciscana Eastw. | Arctostaphylos hookeri ssp. franciscana | Ericaceae
|
| ARGA4 | Arctostaphylos gabrielensis P.V. Wells | San Gabriel manzanita | Ericaceae
|
| ARGLA2 | Arctostaphylos glandulosa Eastw. ssp. adamsii (Munz) Munz | Adams' manzanita | Ericaceae
|
| ARGLC4 | Arctostaphylos glandulosa Eastw. ssp. crassifolia (Jepson) P.V. Wells | Del Mar manzanita | Ericaceae
|
| ARGLG3 | Arctostaphylos glandulosa Eastw. ssp. glandulosa | Eastwood's manzanita | Ericaceae
|
| ARGLG4 | Arctostaphylos glandulosa Eastw. ssp. glaucomollis P.V. Wells | Eastwood's manzanita | Ericaceae
|
| ARGLH2 | Arctostaphylos glandulosa Eastw. ssp. howellii (Eastw.) P.V. Wells | Arctostaphylos glandulosa ssp. zacaensis | Ericaceae
|