Erect, annual herbs. Leaves sometimes basal, usually cauline, or both, basal rosulate, cauline opposite, usually differing in shape to basal, loosely arranged, pedicellate or sessile. Inflorescecne a terminal simple usually 1-flowered. Flowers bisexual, actinomorphic, 4-merous, campanulate. Calyx divided more than half way the length, not provided by an inner membrane, lobes equal in length and breadth. Corolla campanulate, red or yellow, plicae or subsidiary lobes of the corolla absent, naked inside i.e. without any ciliae or fimbriae. Stamens equalling and alternating the corolla lobes. Anthers strictly versatile, with filaments running down approximately to the base of corolla tube. Nectaries present at the base of the corolla tube, corresponding to the number of petals, alternating with stamens and opposite the petals, but never at the base of ovary. Ovary superior, unilocular with numerous ovules and parietal placentation, stigmas 2, usually coiled with distinct style. Capsule ovoid or cylindric, sessile or stipitate, dehiscing septacidally from apex. Seeds light brown, elliptic ovoid or circular shaped, reticulate or smooth.