Plants perennial (short-lived, some­times flowering first year), (1.5–)2.5–35(–45) cm, strigu­lose, hairs basifixed. Stems decum­bent or prostrate with ascending tips, strigulose. Leaves (2–)3–9(–11.5) cm; stipules 2–5 mm, submembra­nous; leaflets (7 or)9–21, blades obovate, oblong-obovate, broadly oblanceolate, oval, or oval-suborbiculate, 2–12(–15) mm, apex obtuse or emarginate, surfaces strigulose abaxially, glabrous or glabrescent adaxially. Peduncles incurved-ascending, (3–)4–14(–15) cm. Racemes (4–)6–20(–25)-flowered, flowers ascending to spreading; axis (1–)1.5–9 cm in fruit; bracts 0.8–3(–3.5) mm; bracteoles 0 or 1. Pedicels 0.5–3.2 mm. Flowers 8.5–12 mm; calyx 5–7 mm, strig­ulose, tube 3.6–4.9 mm, lobes lanceolate-subulate, 0.5–1.3 mm; corolla pink-purple, wing tips often whitish, keel maculate; banner recurved through 45°; keel 6.5–8.4 mm, apex bluntly deltate, beak narrowly triangular or subulate. Legumes ascending, green or purplish becoming stramineous or brownish, slightly incurved, linear-lanceoloid to linear, 3-sided compressed, (13–)15–22 × 2.3–3.5(–4) mm, papery, strigulose. Seeds (17 or)18–26. 2n = 28.

Phenology: Flowering (Jan–)Mar–Jun (summer).
Habitat: Among live oaks, mesquite, cholla, in juniper forests, common on caliche soils in live oak woodlands.
Elevation: 800–2000 m.

Distribution

• Generated Map
• Legacy Map

Ariz., N.Mex., Mexico (Chihuahua, Sonora).

Discussion

Astragalus nothoxys occurs from east-central Arizona to southwestern New Mexico, and into northwestern Mexico. The keel beak has been compared, irrelevantly, to that of Oxytropis (S. Watson 1871), in which the cusp is terminal, not lateral as in this species. Astragalus nothoxys contains swainsonine and is known to be poisonous to livestock (L. F. James and S. L. Welsh 1992).

Selected References

None.

Lower Taxa

None.