Oxytropis lambertii commonly known as purple locoweed, Colorado locoweed, Lambert's crazy weed, or Lambert’s Locoweed is a species of flowering plant in the legume family.
Oxytropis lambertii is a perennial herb producing a patch of basal leaves around the root crown, and several showy erect inflorescences. The leaf is compound with several silvery-green leaflets. The inflorescence produces several flowers, each borne in a tubular purple or pinkish calyx of sepals covered thinly in silver hairs. The pealike flower corolla is reddish or bluish purple with a lighter patch at the base of the banner. The fruit is a cylindrical legumepod.