Herbs or shrubs, sometimes parasitic, usually with twining stems, occasionally prostrate or creeping, or erect, very rarely trees, often with milky juice. Leaves mostly spirally arranged, in parasitic species absent or nearly so, usually petioled; petiole sometimes with extra-floral nectaries. Stipules absent, pseudostipules (leaves of axillary shoot) rarely present. Inflorescences mostly cymose, one- to many-flowered, with mostly opposite or subopposite bracts at the base of the cymes or under the solitary flowers; rarely racemose. Flowers generally hermaphrodite, actinomorphic, rarely slightly zygomorphic, usually 5-merous, rarely 4-merous, various in size and colour, often showy. Sepals usually free, imbricate, with quincuncial aestivation, often persistent, sometimes accrescent in fruit. Corolla sympetalous, of various shapes, often funnel-shaped or campanulate, more rarely rotate, salver-shaped or urceolate; the limb nearly entire or more or less deeply lobed, often contorted-plicate in bud, or valvate or induplicate-valvate. Stamens isomerous, alternating with the corolla-lobes, adnate to the corolla, with usually slender, often filiform filaments and introrse or laterally and longitudinally dehiscing anthers. Pollen smooth or spinulose. Disk mostly present, annular or cupular. Ovary superior, mostly of 2 carpels, 2- or 1-celled, sometimes 4-celled by development of accessory partitions, rarely of 3 carpels and 3-celled; ovules 2 in each carpel, sessile, erect, anatropous. Style 1, often filiform, simple or forked, or 2 free styles, rarely very short or absent. Stigma entire or 2-lobed, rarely 3-lobed, or stigmas 2-4, of various shape, globular or ellipsoid to filiform, sometimes applanate, rarely peltate, kidney-shaped, conical or funnel-shaped. Fruit a capsule dehiscing by valves or circumscissile or irregularly dehiscing, rarely a berry or nut-like. Seeds as many as ovules or fewer; endosperm cartilaginous; cotyledons generally folded, sometimes obscure or absent.
Distr. Ca 55 genera, with ca 1650 spp., widely distributed in the tropical, subtropical and temperate regions of both hemispheres; the greater part of the species in the tropics and subtropics of America and Asia. The larger genera Cuscuta (ca 165 spp.), Convolvulus (ca 250 spp.) and Ipomoea (ca 500 spp.) nearly throughout the range of the family but Convolvulus more in the temperate parts and Ipomoea more in the tropics and subtropics. Other large genera as Evolvulus (ca 100 spp.) and Jacquemontia (ca 120 spp.) nearly confined to America. Argyreia (ca 90 spp.) confined to tropical Asia. Malaysia, and a single sp. in Australia, and Merremia (ca 80 spp.) circumtropical. Several monotypic or small genera in E. Africa, Madagascar, and Australia