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, obtuse, strigulose on both sides 2-3.5 mm long, 1-1.6 mm wide; peduncles 1-7 cm long, racemes with (1)2-4 ascending flowers; flowers pea-like; calyx 2.3-3 mm long, the tube 1.7-0.9 mm long; petals whitish or tinged violet; pods spreading or pendulous, the body ellipsoid, subinflated, 9-9.8 mm long, 4.5-4.6 mm thick, slightly dorsiventrally compressed, thin-walled, red-mottled, unilocular; ovules 8-10. Flowers in May.
Astragalus knightii can be distinguished from A. heilii by the presence of dolabriform hairs on A. knightii. Astragalus heilii is similar to Astragalus kerrii from which it differs by having marcescent leaves and peduncles that form a thatch and the plant is smaller in all parts than for A. kerrii.
New Mexico, McKinley County.
Rim rock ledges of the Mesa Verde Group, in piñon-juniper woodland; 2,195 m (7,200 ft).
An inventory of potential habitat in New Mexico is needed to determine if current land uses pose a threat to this plant.
Welsh, S.L., N.D. Atwood, S. Goodrich and L.C. Higgins. 2003. A Utah Flora, 3rd ed. Monte L. Bean Life Science Museum, Brigham Young University, Provo, Utah.