Description from Flora of China
Herbs annual or perennial. Stem solitary, erect. Leaves lanceolate, elliptic or spatulate, 3- or 5-veined. Inflorescence a cyme, panicle, or capitulum. Calyx cylindric, 15- to 25-veined, not membranous between veins, 5-toothed. Petals 5, red or white, margin entire, emarginate, or 2-lobed; claw long, narrow; coronal scales usually present. Stamens 10. Ovary 1-loculed; styles 2. Androgynophore short. Capsule cylindric or ovoid, crustaceous, dehiscing with 4 teeth. Seeds reniform, tuberculate or striate; embryo annular.
About 30 species: temperate Asia and Europe, mainly in the Mediterranean region; one species in China.
(Authors: Lu Dequan; Magnus Lidén, Bengt Oxelman)