Herbs or shrubs. Leaves opposite; stipules absent or rudimentary but the leaf bases often connected by a raised line. Flowers regular, bisexual or unisexual. Calyx tubular, 4–5-lobed or rarely 2-lobed or cleft. Corolla tubular 4–5-lobed, imbricate or contorted. Stamens 4–5, epipetalous, alternating with the lobes. Ovary superior, 2-locular; placentas axile; style simple but later splitting into 2 from the base in Mitrasacme. Fruit a small capsule. 22 gen., trop. to warm temp.