Annual or perennial herbs. Stipules 0. Leaves opposite, sessile. Inflorescence of terminal, cymose clusters. Flowers 4-5-merous. Sepals free. Petals white, emarginate or 2-fid up to halfway, sometimes 0. Stamens usually 5 (in ours). Styles 5, opposite the sepals. Capsule longer than the sepals, opening by twice as many short teeth as styles.