Fls us. 5-merous, perfect, regular, us. in axillary bracted pairs. Sepals and petals imbricate, stamens free or in fascicles; corona cup-shaped, fleshy, us. with filiform processes or scales. Ovary superior, sts on gynophore, or stamens and pistil on androgynophore. Ovules ∞ on parietal placentae; fr. a loculicidally dehiscent capsule, or a berry. Herbaceous to soft-wooded lianes with lf-opposed tendrils, or shrubs or trees. Some 12 genera and over 600 spp., mostly of tropical America; a few in Africa, Madagascar, Asia. The N.Z. genus is endemic and monotypic.

Herbs or shrubs to small trees, mostly lianes, usually climbing with tendrils. Lvs alternate, mostly with deciduous stipules, entire or variously lobed; petiole often glandular. Fls usually solitary or few in cymes, actinomorphic, usually ☿, sometimes unisexual. Bracts often prominent. Sepals (1)-5, imbricate, free or partially united, often petaloid. Petals usually (3)-5, rarely 0, imbricate, free or nearly so; corona present on receptacle margin, composed of 1 or more rows of thread-like filaments or scales, sometimes merely an annular rim. Stamens (3)-5-(10), alternate with petals; filaments free or fused, sometimes inserted on a gynophore. Ovary superior, 1-locular, sometimes on a gynophore, with 3-(5) parietal placentas; ovules usually numerous. Fr. a capsule or berry. Seeds with pitted testa and fleshy aril, endospermic.