Capsella bursa-pastoris

Capsella bursa-pastoris, known by its common name shepherd's-purse because of its triangular flat fruits which are purse-like, is a small (up to 0.5 m) annual and ruderal flowering plant in the mustard family Brassicaceae. It is native to eastern Europe and Asia minor but is naturalized and considered a common weed in many parts of the world, especially in colder climates, including British Isles where it is regarded as an archaeophyte, North America and China but also in the Mediterranean and North Africa. Capsella bursa-pastoris is closely related to the model organism Arabidopsis thaliana and is also used as a model organism due to the variety of genes expressed throughout its life cycle that can be compared to genes that are well studied in A. thaliana. Unlike most flowering plants, it flowers almost all year round. Like other annual ruderals exploiting disturbed ground, C. bursa-pastoris reproduces entirely from seed, has a long soil seed bank, and short generation time and is capable of producing several generations each year.