Northern Prairie Wildlife Research Center
Not one of our more striking milk-vetches, lotus milk-vetch is also somewhat uncommon, for it has been collected in only 16 of our 53 counties. The plant occurs across much of the arid west.
The plant is a small perennial, only about 3 inches tall, from a long sturdy taproot. The numerous small, grayish-hairy leaves have two to ten widely separated pairs of leaflets. Flowers are cream-colored to yellow, about one fourth of an inch long, and grow in small loose clusters of about six or so on stalks about as long as the leaves. Small pods (legumes) form in June.
Look for lotus milk-vetch in dry native prairie in areas where the shortgrasses like blue grama grow. I have no specific information on the effects of livestock on this species, but it seems to be mostly avoided by cattle. The plant is not listed, as are many other milk-vetches, as active accumulators of selenium and manufacturers of substances which cause poisoning and "locoing" of livestock.
The milk-vetches are members of the bean family (Fabaceae) that contains our clovers, alfalfas, peanuts, and many other important plants. Fab means "bean" in Latin. The generic name Astragalus is an ancient Greek name of some legume, and also of the ankle-bone. The specific name Lotiflorus means "with flowers of Lotus" in botanical Latin. Lotus milk-vetch was first described for science in 183l by the eminent British botanist and founder of the Journal of Botany Sir William Hooker (1785-1865).