Description from Flora of China
Shrubs or small trees, sometimes climbing. Branches spiny. Leaves alternate, petiolate, leaf blade ovate or elliptic-lanceolate. Inflorescences axillary, pedunculate, 3-flowered cymes, each flower subtended by a persistent, often brightly colored, ovate bract adnate to the pedicel, often grouped into terminal panicles. Flowers bisexual; pedicel adnate to the midvein or the bract. Perianth connate, limb rose or yellow, funnelform, 5-6-lobed, lobes short. Stamens 5-10, included; filaments shortly united at base. Ovary fusiform, stipitate. Style lateral, short linear; stigma fimbriate. Fruit cylindric or clavate, 5-ribbed, without sticky glands. Seed: testa thin; embryo curved, cotyledons convolute, enclosing the endosperm.
About 18 species: native to South America, widely cultivated in tropical and subtropical regions; two species (introduced) in China.