Astragalus millissimus (common name - wooly locoweed) is a perennial plant in the legume family (Fabaceae) found in the Colorado Plateau and Canyonlands region of the southwestern United States.:121
It is hairy a perennial plant growing from 2 to 34 inches (5.1 to 86.4 cm) tall, from a very short stem.:121
It has hairy stems and leaves.:121 "Mollissumus" means "most soft", referring to the hairy covering of the leaves and stems.:121Compound pinnate leaves are from 34 to 11 inches (1.9 to 27.9 cm) long, with 15-35 elliptical to oval and wooly leaflets.:121
It blooms from March to August.:121 The inflorescence are from 34 to 10 inches (1.9 to 25.4 cm) stalks with 7-20 flowers per stalk.:121 Each pink to purple or bicolored with white flower has a 14 to 12 inch (0.64 to 1.27 cm) hairy calyx with 5 pointed teeth, around a 34 inch (1.9 cm) corolla with upper petal flares at the end.:12113 to 1 inch (0.85 to 2.54 cm) seed pods are egg shaped and densely hairy.:121
It grows from grasslands to Pinyon juniper woodland communities ranging from Wyoming to Arizona.:121
It derives its common name from its wooly stems and leaves, and because it makes livestock "go loco" or die from an alkaloid it contains called Iocoine.