Annual or perennial herbs or dwarf-shrubs. Stems slender. Leaves opposite, small, exstipulate. Flowers many in terminal Or axillary dichasial cymes or sometimes solitary. Sepals 5, free. Petals 5, rarely 0, white or pink, entire or emarginate. Stamens 10(5), inserted on a nectariferous disk. Ovary 2-5-carpelled, 1-celled, many-ovuled; styles 2-3 (rarely 4-5). Capsule dehiscing to base by 6 entire or 3-fid valves. Seeds usually reniform, tuberculate.