Erect, creeping, scrambling or twining herbs and shrubs, sometimes succulent, usually with milky latex. Leaves opposite, simple, sometimes reduced or absent, exstipulate, entire. Flowers actinomorphic, bisexual, 5-meous, in terminal or lateral umbelloid, corymbose or paniculate cymes. Sepals united, shortly connate or almost free, imbricate. Corolla gamopetalous, rotate, campanulate, tubular, lobes valvate or twisted in bud, rarely imbricate. Stamens 5, epipetalous, alternating with corolla lobes, either connivent by the anthers (Periplocoideae) or completely connate and adnate to the style apex forming a gynostegium (Asclepiadoideae). Corona of one or two series, attached to the corolla or to the staminal column or the outer series to the corolla and the inner to the staminal column. Anthers longitudinally dehiscent or opening by terminal slits. In Periplocoideae the pollen grains are in tetrads and fall into spatulate pollen carriers with adhesive disc formed on the surface of the style apex between the anthers. In Asclepiadoideae 1 or 2 pollinia (waxy masses) per anther locule are present; the pollinia of adjacent locules of adjacent anthers are connected by the translator apparatus, which consists of a corpusculum and two arms or retinaculae, each of which bears a pollinium. Carpels 2, superior, united only by the enlarged style apex, multiovulate, placentation parietal. Fruit of 2 distinct or single (by abortion) follicles. Seeds flattened, without an aril, comose.