Hairy vetch (Vicia villosa)is an annual, biennial, or rarely perennial, trailing or climbing legume. V. villosa is found throughout all 50 states in the United States and in other temperate climates worldwide. It is cultivated for its use as a pasture grass and cover crop. It's leaves consist of 10-20 narrowly oblong to linear-lanceolate leaflets, with branched tendrils. The stems and leaves of V. villosa are usually covered with soft woolly fuzz. It produces clusters of 10-40 purple flowers and flattened, elongated, green seedpods containing round black seeds.
Toxic components V. villosa is capable of accumulating large amounts of dry matter, nitrogen and cyanogenetic glycosides.