Perennial herbs with trailing or twining stems, more or less glabrous, hairs simple (when present). Leaves simple, entire or lobed, often sagittate or hastate, petiolate. Inflorescences axillary. Flowers solitary (in Victoria) or rarely in few-flowered cymes, usually white or pink; bracteoles large and enclosing the calyx; sepals 5, free, subequal; corolla funnel-shaped or campanulate, entire or slightly 5-lobed, distinct glabrous mid-petaline bands present; stamens 5, subequal, included, filaments hairy on the fused basal margins; ovary 1- or incompletely 2-celled, glabrous, ovules 4, style 1, stigma 2-lobed, lobes oblong or elliptic. Capsule ovoid or globose, splitting longitudinally into 4 valves; seeds 4 per capsule, smooth, glabrous.
About 25 species, mainly from temperate regions of the world; 4 species in Australia (1 naturalized).