Description from Flora of China
Herbs annual. Stems erect. Leaves narrowly lanceolate to linear. Flowers in few flowered, lax dichasia. Calyx tube ovate or elliptic-ovate, with 10 longitudinal, raised veins; teeth 5, leaflike, linear, usually longer than tube. Androgynophore absent. Petals 5; limb usually shorter than calyx teeth, emarginate, gradually turning to claw; coronal scales absent. Stamens 10. Ovary 1-locular; styles 5, hairy, alternating with calyx lobes. Capsule ovoid, septicidally dehiscing by 5 teeth. Seeds numerous.
About three species: native to the Mediterranean region, native or naturalized in N Asia and Europe, naturalized in North America; one species in China.
(Authors: Lu Dequan; Magnus Lidén, Bengt Oxelman)