shepherd's purse

shepherd's-purse, annual herb (Capsella bursa-pastoris) of the family Cruciferae (mustard family), indigenous to Europe but now a nearly cosmopolitan weed in temperate regions. It is also called pickpocket, and both the Latin and common names derive from the peculiarly shaped triangular seed pods. A decoction from the plant, containing the alkaloid bursin, has been used medicinally as an antidysenteric, a diuretic, and a febrifuge. Capsella is classified in the division Magnoliophyta, class Magnoliopsida, order Capparales, family Cruciferae.