Hesperothamnus brachycalyx Rydb.

Hesperothamnus brachycalyx Rydberg, sp. nov
A low shrub; bark of the stem dark-gray; young branches finely velutinous; stipules caducous; leaves 6-10 cm. long; rachis finely velutinous; leaflets 5, broadly oval, 2-4 cm. long, 1.5-3.5 cm. wide, strongly veined, densely and finely strigose on both sides when young, glabrate in age above, rounded or somewhat subcordate at the base, acute to rounded at the apex; racemes 5-8 cm. long; flowers rather crowded; calyx silky, the lobes scarcely 2 mm. long, the upper one broadly ovate and rounded or slightly retuse at the apex, the lower three ovate, acute or obtusish; corolla 10-13 mm. long, similar to that of H. grandis; pod unknown.
Tvpe collected six miles above Dominguillo, Oaxaca, E. IT'. Nelson 1826a (U. S. Nat. Herb, no. 763608).

Hesperothamnus brachycalyx is a species of flowering plants in the family Fabaceae. It is a low shrub with the bark of the stem dark - gray and young branches finely velutinous. It is native to southwest Mexico.