Northern Prairie Wildlife Research Center
In North Dakota, only the extreme southwest is home to painted milk-vetch. Elsewhere, this Great Plains dweller ranges from southern Utah and Montana south to Texas and Arizona at elevations under 8,000 ft.
Painted milk-vetch is a weak-stemmed perennial from a slender, branched caudex (hardened stem base). Stems are up to 20 inches long, and can be erect or decumbent. The plants appear leafless, as the long leaves have only a few narrow leaflets and are borne on long slender petioles. A few tiny whitish to purplish flowers form at the tips of the branches. It is the legumes (seedpods) that give painted milkvetch its common name and distinctive appearance. These legumes are up to 2 inches long, inflated, and look like bird's eggs mottled in red or purple. At maturity, the legumes contain smooth brown seeds.
Look for painted milk-vetch in June in sandy native prairie or sand dunes that are not overgrazed. I could find no information as to any economic uses for this milk-vetch. In ancient Greece, certain members of the genus were supposed to increase the secretion of milk in goats, but many of the so-called milk-vetches are notorious poisoners of livestock and can cause "locoing."
The generic name Astragalus is an ancient Greek name for some member of the bean family (Fabaceae) and also of the ankle bone. Fab means "bean" in Latin. The genus contains about 1,500 species. The specific epithet crassicarpus was compounded from the Latin by botanists to mean "thick-fruited." Painted milk-vetch was first described for science in 1894 by Astragalus expert Edmund Perry Sheldon (1869-?), resident of Minnesota and later of Oregon where he specialized in forestry.