Plants stout, usually erect, herb­age sparsely hairy or stems gla­brous. Leaflets 17–29, (5–)10–25(–32) mm. Racemes 25–75-flowered; axis 5–18 cm in fruit; bracts (2–)2.5–7 mm. Flowers 13–17.5 mm; calyx usu­ally red-purple, tube 3.3–5.7 mm, lobes 1.5–4.5(–6) mm; corolla pink-purple, or pallid and purple- or lilac-tipped or suffused, or white or whitish and keel tip maculate; banner longer than keel. Legumes linear- or narrowly oblong-ellipsoid, (8–)10–17(–20) × 2–4.5 mm, smooth or faintly retic­ulate, glabrous or strigulose; stipe 3–5(–6) mm. Seeds 10–14(or 15). 2n = 22, 24.

Phenology: Flowering May–Aug.
Habitat: On fine-textured, saline or seleniferous substrates, short-grass prairies, plains, bad­lands, in steppes, with sagebrush-grass, shadscale, less commonly with pinyon-juniper and mountain brush communities.
Elevation: 400–2500 m.

Distribution

• Generated Map
• Legacy Map

Loading map...

Alta., Man., Sask., Colo., Idaho, Kans., Mont., Nebr., N.Mex., N.Dak., Okla., S.Dak., Utah, Wyo.

Discussion

Variety bisulcatus has been confused with Astragalus racemosus, with which it sometimes intermingles. The gibbous calyx of A. bisulcatus and two-grooved versus ± three-sided fruit serve to distinguish them. Where they are sympatric, A. bisulcatus is usually purple-flowered. The vars. bisulcatus and haydenianus are known to contain selenium and swainsonine, both poisonous to livestock (S. F. Trelease and O. A. Beath 1949; J. M. Kingsbury 1964).

Selected References

None.

Lower Taxa

None.