Plants 50–120 cm, densely silky-strigulose. Stems erect or ascending, densely silky-strigulose. Leaves (5–)7–17(–20) cm; stipules connate-sheathing at proximal nodes, distinct at distal nodes, 2–14 mm, scarious; leaflets (17–)21–35, blades linear, linear-oblong, -elliptic, -lanceolate, or -oblanceolate, (3–)6–26 mm, apex obtuse and apiculate or emarginate, surfaces strigulose, sometimes glabrous adaxially. Peduncles erect, 6–24 cm. Racemes 15–45-flowered, flowers nodding; axis (5–)7–17 cm in fruit; bracts 1.5–4 mm; bracteoles 0–2. Pedicels 1.2–5 mm. Flowers 12.6–17.6 mm; calyx (6.5–)8–11.4 mm, densely silky-strigulose, hairs white, tube 5–7.2 mm, lobes lanceolate-subulate, (1.5–)2–4.2 mm; corolla ochro­leucous, immaculate; banner gently and slightly recurved; keel 11.5–14.7 mm. Legumes spreading to pendulous, stramineous, obliquely ovoid-ellipsoid or semi-ovoid, bladdery-inflated, somewhat compressed laterally, (20–)25–43 × 13–18 mm, thin becoming papery-membranous, translucent, lustrous, sparsely strigulose; stipe filiform, 14–40 mm, pubescent. Seeds (16–)18–30. 2n = 22.

Phenology: Flowering Apr–Jul.
Habitat: Dry, grassy hills, fields, roadside banks, rolling plains.
Elevation: 50–1000 m.

Distribution

• Generated Map
• Legacy Map

Calif.

Discussion

Astragalus asymmetricus is known from the inner South Coast Ranges and adjoining Great Valley, from western Kern County and the Salinas Valley, San Luis Obispo County, northward through the hill country east of San Francisco Bay to Solano County.

Astragalus asymmetricus, A. oxyphysus, and A. trichopodus form a trio of very similar southern California species. R. C. Barneby (1964) contrasted the first and last in a key. Astragalus asymmetricus has con­nate proximalmost stipules, longer calyces, and slightly graduated petals. It is also well known in California as poisonous to stock, containing swain­sonine (L. F. James and S. L. Welsh 1992).

Selected References

None.

Lower Taxa

None.