Acmispon tomentosus is a perennial plant in the family Fabaceae in the genus Acmispon. It is native to California and northwestern Mexico.[1] The variety A. tomentosus var. glabriusculus has the synonym Acmispon heermannii.
The species is identified by small oval hairy succulent leaves. the flower buds are burgundy red and the flowers are yellow, looking much like a small version of a Lotus pedunculatus flower head.
Sometimes this species occurs as an annual plant if it is growing in certain conditions.[2]
The species was first described by William Jackson Hooker and George A. Walker Arnott in 1832 as Hosackia tomentosa. It was moved to the genus Acmispon in 2018.
, Plants of the World Online accepted two varieties:
A. tomentosus var. glabriusculus has the synonym Acmispon heermannii, and has been known by the common name Heermann's bird's-foot trefoil., Plants of the World Online and the Jepson eFlora accept this variety rather than the species A. heermannii.[3]
A. tomentosus var. tomentosus is generally identified by having less red in its buds and more hairy leaves.[4]