Plants forming small tufts, sub­acaulescent or shortly caules­cent, slender, 4–7(–10) cm, strigulose, hairs basifixed; from caudex, ± with persistent leaf bases; taproot slender. Stems prostrate, 0.5–3(–7) cm, internodes short, length slightly 2 times stipules, strigulose. Leaves 2–10 cm; stipules distinct throughout, 1–4 mm, papery-scarious; leaflets 11–15(or 17) blades linear-elliptic or oblanceolate, 3–10 mm, apex acute or obtuse, surfaces usually strigulose, sometimes glabrescent adaxially. Peduncles ascend­ing, (1.5–)2.5–8 cm. Racemes 2–5-flowered, flowers ascending; axis 0.5–2 cm in fruit; bracts 1.5–2.5 mm. Pedicels 1.5–2 mm. Flowers 9.5–11 mm; calyx purplish, cylin­dric or campanulate, 5–5.5 mm, strigulose, tube 3–3.5 mm, lobes subulate, 1.5–2 mm; corolla ochro­leucous, banner and keel with purple tips or veins; keel 7–7.5 mm. Legumes separating from receptacle at maturity, ascending (humistrate), red-mottled, gently incurved, narrowly oblong, slightly 3-sided compressed, 12–20 × 3.5–5 mm, sub-bilocular, thin becoming papery, sparsely strigulose; septum partial, 0.2–0.6 mm wide; sessile, gynophore to 1 mm. Seeds 8–10.

Phenology: Flowering May–Jun.
Habitat: Ledges of sandstone cliffs, sand-filled depressions of flat or shelving rock, on loose, sandy talus on slopes below rimrock.
Elevation: 2000–2100 m.

Distribution

• Generated Map
• Legacy Map

Colo.

Discussion

Astragalus deterior is known only from the southern end of Mesa Verde, on Chapin Mesa, in Montezuma County. It was initially mistaken for the related A. naturitensis, but differs in its smaller, ochroleucous flowers, connate stipules, and narrower fruits of thinner texture that are borne on distinct gynophores.

Astragalus deterior is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Selected References

None.

Lower Taxa

None.