Description from Flora of China
Herbs twining, often with winged stems, peduncles, and petioles. Leaves petiolate, angular or palmate, base often cordate, margin entire. Flowers axillary, solitary or in few-flowered cymes; bracts deciduous, often foliose. Sepals often enlarged in fruit, margin becoming irregularly lacerate. Corolla broadly funnelform, rarely campanulate or nearly salverform, glabrous or midpetaline bands pubescent outside. Stamens included (exserted in 1 sp.); filaments adnate to corolla tube basally, filiform distally; anthers often spirally twisted at dehiscence; pollen 3-colpate, not spiny. Disc ringlike. Ovary 2-loculed, 4-ovuled, glabrous. Style filiform, included; stigma 2-globose. Fruit circumscissile in or above middle, distal portion lidlike, ± fleshy, separating from papery endocarp, which shatters irregularly. Seeds 4 or fewer, trigonous or globular, glabrous or angles pilose.
About 15 species: worldwide in the tropics; one species in China.