Plants densely mat-forming or bushy or mounded or, some­times, erect clumps, 20–100 cm, sparsely villosulous; from superficial caudex. Stems dif­fuse, prostrate, ascending, or erect, sparsely villosulous. Leaves (2.5–)4–17 cm; stipules connate-sheathing at proximal nodes, mostly connate at distal nodes, 3–14 mm, membranous; short-petiolate or subsessile; leaflets (21 or)23–43, blades obovate, obovate-cuneate, oblong-obovate, narrowly to broadly oblong, or oblanceolate, (2–)3.5–25(–28) mm, apex retuse, emarginate, obtuse, or obtuse and apiculate, surfaces villosulous, sometimes sparsely so or glabrous adaxially, rarely puberulent. Peduncles erect or incurved-ascending, (4–)6–15(–18) cm. Racemes (15–)20–90(–125)-flowered, flowers nodding; axis 3–19 cm in fruit; bracts 1.5–4(–5) mm; bracteoles 0–2. Pedicels 0.8–5.5(–7) mm. Flowers (10–)11–15 mm; calyx campanulate or ovoid-campanulate, gibbous abaxially, (5.5–)5.8–8.2(–9) mm, sparsely to densely villosulous or loosely strigulose, tube (4–)4.3–5.7(–5.9) mm, lobes broadly subulate or triangular, (1.1–)1.3–3(–3.1) mm; corolla greenish white or cream; keel (9.7–)10.5–14 mm. Legumes loosely spreading, ascending, or declined, pale green or minutely purple-dotted, becoming stramineous, obliquely ovoid, ovoid-ellipsoid, or semi-ovoid, semi-obovoid, or semi ovoid-ellipsoid, bladdery-inflated, (20–)25–55(–60) × 15–27 mm, thin becoming papery, lustrous, glabrous or villosulous; sessile. Seeds (14–)16–38. 2n = 22.

Distribution

California.

Discussion

Varieties 2 (2 in the flora).

Astragalus nuttallii is the only Astragalus with sessile, bladdery fruits found at the shoreline or on sea bluffs in central California.

Selected References

None.

Lower Taxa

Astragalus nuttallii var. nuttallii, Astragalus nuttallii var. virgatus

Key

1	Legumes villosulous; stems diffuse or prostrate; herbage green, cinereous, or canescent; leaflet blades equally pubescent or sparsely so adaxially; seeds (22–)28–38; maritime, Monterey Bay southward to Point Conception, California.	Astragalus nuttallii var. nuttallii
1	Legumes glabrous or sparsely villosulous; stems strongly ascending or erect; herbage green or greenish cinereous; leaflet blades usually glabrous adaxially, rarely puberulent; seeds (14–)16–21; maritime or slightly inland, San Francisco Peninsula (and formerly on Bay shore) and maritime northward to Mendocino County, California.	Astragalus nuttallii var. virgatus