Plants slender, (20–)25–50 cm, glabrous or sparsely villous; from superficial caudex. Stems spreading to ascending, gla­brous or glabrate. Leaves 4–12 cm; stipules 3.5–9.5 mm, papery at proximal nodes, submembranous at distal nodes; leaflets (11–)15–23, blades broadly oblong, ovate, or obovate to sub­orbiculate, (4–)6–16(–20) mm, apex retuse or abruptly short-acuminate, surfaces glabrous, sparsely ciliate, abaxially with few hairs on midrib. Peduncles erect or incurved-ascending, 5–12 cm. Racemes 10–25-flowered; axis (1.5–)2–5 cm in fruit; bracts 1.7–4 mm; bracteoles 0. Pedicels 0.6–1.2 mm. Flowers 10–14 mm; calyx 5.2–7 mm, sparsely strigulose, tube 3.1–4 mm, lobes subulate, 2.1–3.2 mm; corolla greenish white, immaculate, often drying cream; banner recurved through 40–60°; keel 7.7–10 mm. Legumes spreading or declined, stramineous or blackish, incurved to 0.5 spiral, lunately or falcately linear-lanceoloid or linear, 3-sided, 14–24 × 2.6–3.6 mm, firmly papery, glabrous; septum 1.5–2.3 mm wide; stipe 0.8–1.9 mm. Seeds 10–15.

Phenology: Flowering May–Jul.
Habitat: Oak and pine woodlands.
Elevation: 100–1300 m.

Distribution

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Calif., Oreg.

Discussion

The wide morphological gap between Astragalus umbraticus, restricted to the Cascade Range of Oregon and Coast Ranges of northwestern California, and its closest relatives is suggestive of age and a long period of isolation (R. C. Barneby 1964).

Selected References

None.

Lower Taxa

None.