Astragalus drummondii
Fl. Bor.-Amer. 1: 153, plate 57. 1831.
Plants robust, stout, 25–60(–65) cm, softly villous-hirsute or shaggy-villous, hairs minutely dilated at base; caudex branched. Stems erect or ascending, softly villous-hirsute or shaggy-villous. Leaves 4–13 cm; stipules connate-sheathing or distinct at proximal nodes, distinct at distal nodes, (2–)3–12 mm, submembranous becoming papery-scarious; leaflet blades oblong to oblanceolate or obovate, 4–33 mm, apex obtuse to truncate or emarginate, surfaces villous-pilose abaxially, glabrous adaxially. Peduncles erect, 4–12(–15) cm. Racemes 14–30-flowered; axis 3–22 cm in fruit; bracts 2–5 mm; bracteoles 0–2. Pedicels 1.5–5 mm. Flowers (16–)18–25 mm; calyx 7–12.5 mm, sparsely villous, tube 4.7–8 mm, lobes subulate, 1.7–4.5 mm; corolla keel 12–15 mm. Legumes stramineous, 17–32 × 3.5–5.5 mm, fleshy becoming stiffly papery or leathery, glabrous; septum 0.6–1.5 mm wide; stipe 5–11 mm. 2n = 22.
Phenology: Flowering May–Aug.
Habitat: Prairies, plains, grasslands, montane, or steppe sites in oak brush, sagebrush, pinyon-juniper and ponderosa pine communities.
Elevation: 500–2700 m.
Distribution
Alta., B.C., Sask., Colo., Idaho, Mont., Nebr., N.Mex., N.Dak., S.Dak., Utah, Wyo.
Discussion
Astragalus drummondii is easily recognized by a combination of the ochroleucous or white, nodding flowers, the shaggy pubescence, and the pendulous, glabrous fruits; it contains swainsonine and is therefore potentially poisonous to livestock (W. E. Fox et al. 1998).
Two historic collections from Oregon appear to have been isolated introductions.
Selected References
None.