Capsella rubella, the pink shepherd's-purse, is a plant species in the genus Capsella, a very close relative of Arabidopsis thaliana and a member of the mustard family, Brassicaceae. It has a very similar appearance to Capsella bursa-pastoris, but C. rubella has a diploid genome, whereas C. bursa-pastoris is tetraploid. Capsella rubella is used as a model plant to study the evolution of self-incompatibility into self-compatibility in plant reproduction. The species is found mostly in Mediterranean ...