Annual or perennial herbs, glabrous or rarely hairy. Stems erect or prostrate. Leaves simple, alternate, opposite to subopposite or subverticellate, often in a basal rosette, usually exstipulate. Inflorescences terminal or in seemingly axillary cymes, rarely as a solitary flower. Flowers small, usually bisexual, actinomorphic, usually hypogynous. Sepals 5, rarely 4, free or connate below into a tube, lobes white or pink to purple, persistent. Petals absent, petaloid staminodes often present. Stamens 3-5(-20), free or connate at base in bundles, anthers bithecous, dehiscence longitudinal. Carpels 2-5 or many, syncarpous, ovary superior, placentation axile, rarely seemingly basal. 1-many ovules per loculus; stigmas as many as carpels/ locules. Fruit usually a dry membranous loculicidal capsule dehiscing usually by 3-5 valves or (3-) 5-15-lobed mericarps.
11 genera and about 103 species