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Woollypod Milk-vetch Astragalus purshii


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Woollypod Milk-vetch
credit: Matt Brown, U.S. Forest Service

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Alternate name: Woollypod Locoweed, Pursh's Milk-vetch

Family: Fabaceae, Pea view all from this family

Description Habit: native perennial herb, finely silver-hairy.
Height: 3-6 in (7.5-15 cm)
Leaf: alternate, odd-pinnate, to 5 in (12.5 cm) long; 3-17 leaflets, oval to narrowly lanceolate, tips notched or rounded, to 0.6 in (15 mm) long.
Flower: purple to lavender to pink to cream, 0.25-0.67 in (6-17 mm) long; in linear cluster of 2-12 flowerheads, along incurved or prostrate stalk, held in leaf axil.
Fruit: fuzzy pod, straight or slightly curved, to 1 in (25 mm) long and 0.5 in (12 mm) wide, resembling a large cotton ball.

Warning All plants in the genus Astragalus are potentially toxic to humans and animals if ingested, causing a disorder called locoism. The milk from an animal that has ingested Astragalus plants may also be toxic. Sensitivity to a toxin varies with a personís age, weight, physical condition, and individual susceptibility. Children are most vulnerable because of their curiosity and small size. Toxicity can vary in a plant according to season, the plantís different parts, and its stage of growth; and plants can absorb toxic substances, such as herbicides, pesticides, and pollutants from the water, air, and soil.

Flower March to April.

Habitat Disturbed rocky soils; dry plains, slopes, juniper or sagebrush communities, shrub-steppes; also cultivated as an ornamental.

Range Native to northwestern North America, from British Columbia south to California, east to Coloroado, north to Wyoming, the Dakotas, and Saskatchewan.

Discussion Also called Pursh's milkvetch. Eight varieties are proposed. The Thompson Indians of British Columbia poured a tea made from woollypod milkvetch onto hunting equipment which had lost its luck.