Montana Field Guide

Cushion-forming from a branched caudex. Herbage silky-strigose with dolabriform hairs. Stems <3 cm long, clothed in stipules. Leaves trifoliolate; leaflets oblanceolate, 3–10 mm long, acute; stipules hyaline, 2–7 mm long, united behind the petiole. Inflorescence of 1 or 2 flowers, shorter than leaf petioles. Flowers ochroleucus; sepals 3–4 mm long; calyx white-sericeous; banner slightly reflexed, 12–15 mm long; keel 8–12 mm long, purple-tipped. Legume ascending, ovoid, 4–8 mm long, sericeous, hidden among leaves (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Similar to Astragalus purshii, from which it differs in having longer, more ascending stems (stems over 1.5dm). It also has longer calyx teeth than A. purshii (>4mm). Species of Oxytropis may appear similar, but lack elongated, leafy stems.

Sagebrush steppe and sparsely vegetated slopes.

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans, Bombus appositus, Bombus auricomus, Bombus bifarius, Bombus borealis, Bombus centralis, Bombus fervidus, Bombus flavifrons, Bombus huntii, Bombus mixtus, Bombus nevadensis, Bombus rufocinctus, Bombus ternarius, Bombus terricola, Bombus occidentalis, Bombus pensylvanicus, Bombus griseocollis, and Bombus insularis (Macior 1974, Thorp et al. 1983, Mayer et al. 2000, Colla and Dumesh 2010, Wilson et al. 2010, Koch et al. 2012, Miller-Struttmann and Galen 2014, Williams et al. 2014).