Fabaceae : Oxytropis lambertii

Oxytropis lambertii is an acaulescent perennial herb growing from a branching caudex, forming clumps of leaves that appear silvery due to a covering of short stiff and ax-shaped hairs. The leaves are up to 15 cm long with 7 to 19 linear-lanceolate leaflets, 5-40 mm long and 1-6 mm wide, with membranous, hairy stipules 7–24 mm long and having sharply pointed tips. Inflorescences develop on multiple, silvery-haired flowering stems (scapes), 10–30 cm long including the peduncle, each with 6 to 25 flowers per raceme. The calyx has a dense white covering of hairs, the sepals forming a tube that is 6-7 mm long with teeth 1.5-3 mm long. The papilionaceous flowers have red to blue to purple petals, the banner 15–25 mm long, the wings 12-20 mm long and the keel 13-19 mm long. The fruit is an silvery-haired, erect, sessile leathery or woody legume, 1–2 cm long, including the long beak. Purple locoweed blooms from May into August on prairies, plains, river bluffs and hillsides in much of South Dakota.