Lianas usually glabrous, with latex. Leaves opposite; stipules interpetiolar, reduced to many linear segments. Racemes axillary, few flowered. Flowers large. Calyx deeply divided, with many basal glands inside. Corolla funnelform; tube narrow, more than 2 cm, limb campanulate; faucal scales absent; lobes overlapping to right. Stamens inserted and included in widened part of corolla tube; filaments short; anthers oblong, adherent at middle to pistil head, cells obtusely caudate; disc 5-cleft. Ovaries free, glabrous; ovules numerous. Style glabrous; pistil head with a 2-cleft mucro. Follicles long, slender. Seeds narrowly oblong, not beaked, comose.

About 120 species: Central and South America, one species cultivated in China.