Synonyms: Astragalus striatus Other names: prairie milkvetch Nomenclature: adsurgens = rising, standing up Nativity / Invasiveness: Montana native plant
General: perennial 10-40 cm tall, greenish to rather grayish with short, flat, stiff, T-shaped hairs, stems often several from the base.
Leaves: alternate, about 4-12 cm long, the 9-23 leaflets narrowly oblong to oblong-obovate, 1-2.5 cm long, 3-10 mm broad. Stipules membranous, broadly lanceolate, joined around stem, 5-15 mm long.
Flowers: about 15-80 in oblong, congested, spike-like clusters on main stalks about equaling or up to twice as long as the leaves. Individual flower stalks about 1 mm long. Flowers erect, white or pale purplish to fairly dark purple, 14-18 mm long. Calyx 5-9 mm long, the narrow teeth from about 1/3 as long to nearly as long as the tube, whitish- or blackish-flat-hairy. Banner only slightly bent up, 1-3 mm longer than the wings. Wings 2-3 mm longer than the keel.
Fruits: pods, stalkless, erect, membranous, 8-12 mm long and 3-4 mm thick and broad, with short, flat, base-attached hairs, cordate in section, the lower seam as a broad groove, intruded as a narrow membrane 2/3-3/4 the width of the pod.
Prairie grassland to rocky foothills, in most parts of MT. Also from c. WA to Alberta and MN, s. to NM.
The Cheyenne used ground leaves and stems of standing milkvetch applied to skin affected by poison ivy.
Astragalus adsurgens has been found to accumulate selenium well above the minimum amount of 5 mg/kg required for the existence of selenium poisoning in sheep and cattle. Some plants collected in Canada contained 44 mg/kg of selenium.
Our specimen belong to var. robustior Hook.
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