Perennial or annual herbs, often rhizomatous. Leaves simple, alternate or opposite (rarely all rosetted); stipules absent. Inflorescence a cyme or solitary flower. Flowers bisexual, actinomorphic, usually long-pedicellate; calyx-lobes 5 (rarely fewer), free, more or less narrow-triangular, persisting on mature fruit; corolla blue to purple at least within (rarely white) campanulate, obconical, funnel-shaped or rotate, with (4–)5(–8) spreading lobes; stamens usually 5, free, anthers introrsely dehiscent by longitudinal slits; ovary inferior, 2- or 3-locular (in Victorian species), ovules numerous; style 2- or 3-armed. Fruit a capsule dehiscing by apical slits; seeds numerous, flattened-ellipsoid, dark brown and shining.
About 200 species, mostly in the Southern Hemisphere; 22 species (1 introduced) in Australia.