Description from Flora of China
Shrubs or trees, unarmed; buds conical. Raphides absent. Leaves verticillate or opposite, distichous, usually with domatia; stipules persistent [or sometimes caducous], interpetiolar, triangular, at apex sometimes with a black gland. Inflorescences terminal and sometimes in axils of uppermost leaves, capitate with several globose heads, many flowered, pedunculate, bracteate; bracteoles clavate to clavate-spatulate. Flowers sessile, bisexual, monomorphic. Calyx limb 4(or 5)-lobed. Corolla white to cream, salverform to funnelform, variously pubescent inside; lobes 4, imbricate (and quincuncial) in bud. Stamens 4, inserted in corolla throat, partially exserted; filaments short; anthers dorsifixed, bifid at base. Ovary 2-celled, ovules 1 in each cell, apical and pendulous, anatropous; stigma clavate to capitate, exserted. Fruiting heads globose. Fruit schizocarpous, obconic to turbinate, dry, with calyx limb persistent; mericarps 2, indehiscent, with 1 seed, obconic, stiffly papery; seeds medium-sized, oblong-ellipsoid, with white spongy aril.
Six species: three in the Americas, two in Asia, one in Africa; one species in China.
(Authors: Chen Tao (陈涛); Charlotte M. Taylor)