botany, a genus of plants of the monoecia polyandra clas. The calyx of the male is cylindrical, drical, and has five teeth; the corolla has five petals; and the stamens are from 10 to 15. The calyx of the female consists of many leaves; it has no corolla; but has three bifid stigmas; and the capsule has three cells, and contains one seed. There are 21 species, none of them natives of Britain.