Aegilops cylindrica Host (Synonym : Aegilops cylindrica Host var. kastoriana Karat.)

Family : Poaceae [Naturalized plant]

Aeginetia indica L. (Synonym : Aeginetia japonica Siebold & Zucc.)

Family : Orobanchaceae

Aegopodium alpestre Ledeb. (Synonym : Carum alpestre (Ledeb.) Koso-Pol.)

Family : Apiaceae

Aeschynomene indica L. (Synonym : Aeschynomene roxburghii Spreng.)

Family : Fabaceae

Aesculus turbinata Blume (Synonym : Pawia dissimilis (Blume) Kuntze)

Family : Hippocastanaceae

Aethusa cynapium L.

Family : Apiaceae [Naturalized plant]

Agastache rugosa (Fisch. & C.A.Mey.) Kuntze (Synonym : Agastache rugosa (Fisch. & C.A.Mey.) Kuntze f. hypoleuca (Kudô) H.Hara)

Family : Lamiaceae

Agave americana L.

Family : Agavaceae

Ageratina altissima (L.) R.M.King & H.Rob. (Synonym : Kyrstenia altissima (L.) Greene)

Family : Asteraceae [Naturalized plant]

Ageratum conyzoides L. (Synonym : Ageratum muticum Griseb.)

Family : Asteraceae [Naturalized plant]