Perennial herbs or subshrubs. Leaves subsessile; stipule a sheath bearing 3-15 fimbriae. Flowers often heterostylous, borne in cymes or corymbs or subspherical heads. Calyx with 4 ovate-triangular lobes. Corolla tubular, 4-lobed, often with additional filament-like lobes between.
Ovary 2(-3)-locular; ovules numerous in each loculus. Fruit a subspherical capsule, with a conical beak which opens both loculicidally and septicidally. Comment: Although fairly easily recognized at genus level, the species are often very difficult to distinguish without some doubt since both shape and density of the inflorescences as well as the length of the calyx lobes are quite variable in both species and may sometimes overlap. It is not unlikely that hybrid populations occur in certain areas. Worldwide: Probably only 3 species, confined to tropical Africa and the Comoro Is. Zimbabwe: 4 taxa. |