Mostly climbing shrubs, rarely under shrub, with long pendent or scandent branches. Leaves opposite, rarely alternate, simple, petiolate, entire, glabrous or pubescent, sometimes conspicuously scaly. Inflorescence axillary or extra axillary spike or paniculate. Flowers bisexual or polygamodioecious, bracteoles minute. Hypanthium glabrous or hairy, constricted above the ovary, pitcher, funnel shaped or tubular, 4-5 angled, angles alternating with the calyx teeth, sometimes with additional angles, running into calyx teeth. Calyx lobes 4-5, deltoid to almost subulate or filiform, sometimes scarcely developed, deciduous. Petals equal to the calyx lobes, very rarely absent, (never in the local species) inserted on the calyx limb, usually inconspicuous, glabrous or hairy. Stamens twice as many as the petals, biseriate, usually exserted, anthers dorsifixed or versatile, filaments filiform elongated. Disc intrastaminal, glabrous or pubescent, usually lining the hypanthium, some times absent or very small. Ovary inferior, unilocular with 2-6 pendulous ovule; style subulate; stigma simple. Fruit 4-5 angled or winged, sessile or stalked. 1-seeded.
About 250 species, throughout the tropics of Asia, Africa and America, represented in Pakistan by only 2 species including a cultivated species.