Erect herbs or shrubs; sap milky. Leaves opposite or in whorls of 3, rarely alternate, lacking glands at base of lamina, petiolate. Inflorescences of loose umbels beside upper leaf axils, erect, long-pedunculate. Flowers pedicellate; sepals small, narrow; corolla deeply divided, lobes reflexed; gynostemium elongated, corona-lobes 5, at top of gynostemium, fleshy, erect, elongated, laterally compressed, saccate in upper part, with 2 or 4 teeth on inner side; pollinia 2 per anther, pendent; style-head 5-angled, apex truncate, concave. Follicles ovoid or globose, soft, inflated, with numerous soft spines; seeds many, with a silky coma.
About 50 species from Africa; 3 species naturalised in Australia.
Members of this genus are often included in the closely related Asclepias.