Description from Flora of China
Herbs annual. Stems erect, dichotomously branched. Leaves ovate-lanceolate or lanceolate, base slightly clasping. Inflorescence a corymbose dichasium. Calyx narrowly ovate, 5-toothed, 5-winged at angles, inflated below after anthesis. Petals 5, long clawed. Stamens 10. Ovary 1-loculed; ovules numerous. Styles 2. Capsule ovoid, dehiscing with 4 teeth. Seeds numerous, globose, tuberculate.
One species: temperate Asia and Europe; one species in China.
(Authors: Lu Dequan; Magnus Lidén, Bengt Oxelman)