S1
Critically Imperiled
Astragalus cliffordii (Clifford's Milkvetch)
Caulescent perennial, 3.5-6.5 dm tall; basifixed pubescent; stems buried for 1-6 cm, erect-ascending, forming diffuse clumps; stipules 1.5-4.5 mm long, some connate-sheathing; leaves 3.5-6.5 cm long; leaflets 5-7 (9), linear, acute, strigose, 8-28 m...
Astragalus cobrensis var. maguirei (Maguire's Milkvetch)
Rhizomatous perennial from subterranean caudex; stems few or several, to about 20 cm long, decumbent; herbage with short, stiff, spreading or incurved hairs 0.6-0.8 mm long; stipules connate; leaves 1.5-8 cm long; leaflets broad, glabrous or glabrate...
Astragalus heilii (Heil's Milkvetch)
Low, subcaulescent perennial; basifixed pubescent; stems mostly 2-4 cm long, obscured by stipules and leaf bases; stipules 2-3 mm long, merely amplexicaul or the lowermost connate-sheathing; leaves 1-2.5 cm long; leaflets mostly 7-13, elliptic, obtus...
Astragalus humillimus (Mancos Milkvetch)
Diminutive, tufted, strigulose perennial forming clumps up to 3 dm across; stems up to 1 cm long; leaves crowded, up to 4 cm long, odd-pinnate, leaflets 7-11, oblong-elliptic, 0.7-2.0 mm long, petiole and rachis forming persistent spines after fall o...
Astragalus missouriensis var. humistratus (Pagosa Milkvetch)
Plants strongly caulescent; stems dolabriform pubescent, prostrate, 1-1.5(-2) dm long; leaves 5-14 cm long; leaflets mostly 11-19, obovate or elliptic, 5-15 mm long, 2-3 mm wide; stipules lower connate; inflorescences subumbels with 9-12 ascending or...
Astragalus naturitensis (Naturita Milkvetch)
Low, subacaulescent perennial, about 10 cm tall; stems 2-6 cm long; leaves to 6 cm long; leaflets 9-15 , strigose with straight, overlapping hairs; flowers 3 -11, pea-like, less than 14 mm long; petals bi-colored, banner white with lilac streaks, win...
Astragalus nutriosensis (Nutrioso Milk-Vetch)
Dwarf, acaulescent, perennial herb from a well-developed, short, but knotty caudex on a simple taproot; leaves 3-11 cm long, pinnately compound with 5-9 pairs of leaflets, each leaflet grayish pubescent below and nearly glabrous on the upper surface;...