Acmispon brachycarpus

Herbs, annual, mat-forming, cinereous or greenish, 0.5–4 dm, ± fleshy, villous to pubescent; taprooted. Stems 1–20+, procumbent to low-ascending, branched, herbaceous, leafy. Leaves pinnate or palmate; stipules glandlike, sometimes absent; subsessile or sessile; rachis 4–10 mm, flattened; leaflets (3 or)4(or 5), usually 2 on one side and 2 terminal, blades elliptic to obovate(–oblanceolate), apex usually obtuse, sometimes acute, surfaces villous to pubescent. Peduncles ± sessile; bract absent. Inflorescences 1-flowered. Flowers 5–9 mm; calyx 3–6 mm, accrescent, tube villous, lobes lanceolate; corolla pale yellow, reddish-tipped, turning red, claws shorter than calyx tube, banner horizontal to ascending to 90°, wings ± equaling keel; style curved, glabrous. Legumes persistent, exserted, erect, brown or tawny, straight, compressed, slightly constricted, not septate, oblong, 6–12(–14) × 3–4 mm, stiffly papery, apex obtuse, dehiscent, smooth, margins smooth, thin, villous. Seeds (2 or)3(–5), tan to dark brown or blackish, faintly mottled, lenticular-elliptic (asymmetric), smooth. 2n = 12.

Phenology: Flowering late winter–spring.
Habitat: Rocky, open, disturbed areas, ridges, sand bars, desert flats or washes, stream beds and banks, sandy, gravelly, or clayey soils, serpentine, grasslands, oak-pine woodlands, chaparral, desert scrub, roadsides, agricultural fields.
Elevation: 0–1900(–2000) m.

Ariz., Calif., Idaho, Nev., N.Mex., Oreg., Utah, Mexico (Sonora).

Discussion

Acmispon brachycarpus occurs throughout California into southwestern Oregon (one old collection further north in the Willamette Valley), east through the Mojave Desert into Arizona and southwestern Nevada, and into southwestern New Mexico. Lotus brachycarpus Bentham & Hooker f. ex S. Watson (1878) is an invalid name that pertains here.

Selected References

None.

Lower Taxa