Astragalus racemosus var. racemosus
Leaflets (11–)17–31, blades 3–12 mm wide. Flowers 16–19(–21) mm; corolla whitish, concolorous, or keel tip lilac, wings and banner sometimes lightly suffused with purple or purple-veined. Legumes linear-oblong to narrowly oblong-ellipsoid, (15–)20–30 × 3–5.7 mm. 2n = 24.
Phenology: Flowering May–Jul.
Habitat: Seleniferous bluffs, knolls, alluvial bottoms and roadsides on clay, shale, or gypsum.
Elevation: 500–1400 m.
Distribution
Sask., Colo., Kans., Minn., Mont., Nebr., N.Mex., N.Dak., Okla., S.Dak., Tex., Wyo., Mexico (San Luis Potosí).
Discussion
T. Nuttall (1818) noted the disagreeable garlic odor associated with selenium in his description of Astragalus galegoides Nuttall (an illegitimate name pertaining to A. racemosus). The species often grows intermixed with A. bisulcatus; both are poisonous to livestock, producing so-called alkali disease or the blind-staggers. Variety racemosus does not occur west of the Continental Divide.
Selected References
None.