Erect, annual-perennial glabrous herbs. Basal leaves forming rosette, cauline opposite, loosely arranged, sessile. Inflorescence axillary-terminal, 2-3 flowered cyme. Flowers zygomorphic, long pedicellate, pentamerous. Calyx cylindric-campanulate, 5-lobed, lobes irregularly un equal, never distichous. Corolla 5-lobed, campanulate, variously coloured: pink, purple, blue or white, plicae or subsdiary lobes of the corolla absent, naked inside (without any fimbriae or ciliae), margin of lobes entire. Stamens alternating and corresponding with petals. Anthers versatile, filaments adnate to the corolla tube in the middle or below. Nectaries epipetalous at the base of the corolla tube, double the number of petals. Ovary superior, unilocular with numerous ovules and parietal placentation with a distinct gynaphore, stigmas 2, prominent, sessile or subsessile. Capsule stipitate, ± exserted. Seeds elliptic-oval, striately reticulated or with subsmooth surface.