Acmispon denticulatus
Ann. Bot. Fenn. 37: 130. 2000.
Herbs, annual, cespitose, often glaucous, 0.3–4 dm, not fleshy, glabrous or hirsute; taprooted. Stems 1(–5), decumbent to erect, apically or basally coarse-branched, herbaceous, leafy. Leaves subpinnate, pinnate, or palmate; stipules glandlike or absent; petiolate; rachis 5–12 mm, flattened; leaflets 2–4, often 1 or 2 on one side and 2 terminal, blades elliptic to obovate (lateral sometimes asymmetric), margins denticulate or entire, apex acute to obtuse, surfaces hirsute. Peduncles ± sessile; bract absent. Inflorescences 1 or 2-flowered. Flowers 5–8 mm; calyx 3–5 mm, tube hirsute or glabrous, lobes subulate, ± denticulate; corolla cream-white to pale yellow, banner purple-tinged, keel tip yellowish, claws shorter to slightly longer than calyx tube, banner ascending, wings ± equaling keel, with deep, triangular auricle; style curved, glabrous. Legumes persistent, solitary or paired, exserted, erect or spreading, tawny, straight, compressed, slightly constricted, not septate, widely oblong, 8–20 × 3 mm, leathery, apex abruptly downward angled and curved, dehiscent, smooth, margins often undulate-verrucose, strigose or glabrous. Seeds (2 or)3(or 4), gray, faintly mottled, asymmetrically ± angular-obovoid, flattened, smooth. 2n = 12.
Phenology: Flowering spring–summer.
Habitat: Grassy slopes, meadows, prairies, clearings, gravel bars, stream banks, vernal pools, pastures, grainfields, usually sandy soils, sometimes alkali, clay, or serpentine soils, roadsides.
Elevation: 0–1900 m.
Distribution
B.C., Calif., Idaho, Oreg., Utah, Wash.
Discussion
Acmispon denticulatus occurs in California from the San Francisco Bay area, Sacramento Valley, and northern Sierra Nevada Foothills to the northwest, Cascade Range and Modoc Plateau, into adjacent southern Oregon (Siskiyou and Klamath regions), northward on both sides of the Cascade Range into southern British Columbia, with eastern outliers in southwestern Utah (Washington County), and in south-central Idaho (Lincoln County).
Selected References
None.