Capsella (plant)

Capsella is a genus of herbaceous annual and biennial plants in the family Brassicaceae. It is a close relative of Arabidopsis, Neslia, and Halimolobos. Some authors circumscribe Capsella to contain only three species: Capsella bursa-pastoris, Capsella rubella and Capsella grandiflora. As of 2025, Kew's Plants of the World Online list eight species. Capsella rubella is a self-fertilizing species that became self-compatible 50,000 to 100,000 years ago. Its outcrossing progenitor was Capsella grandiflora. In general, the shift from outcrossing to self-fertilization is among the most common transitions in flowering plants. Capsella rubella is studied as a model for understanding the evolution of self-fertilization. The name is said to derive from Latin capsa, a box or case, alluding to fruit resembling a medieval wallet or purse; the suffix -ella denotes "lesser".