Erect perennial herbs or small shrubs, with milky latex. Lvs opposite or verticillate, sometimes the uppermost alternate, simple. Fls in axillary cymes; cymes umbellate. Calyx small, deeply lobed, glandular inside. Corolla valvate in bud, rotate, deeply 5-lobed; segments becoming reflexed at anthesis. Corona of 5 erect or spreading scales, hood-like, sometimes curved over the anthers, with 2 lateral teeth. Stamens inserted near base of corolla; anthers with an incurved apical membrane; pollinium solitary and pendulous in each cell, attached to a gland on the stigma. Carpels free; stigma 5-angled. Follicles smooth, bristly or softly spinose, inflated.