Annual, tomentose (rarely glabrous) herbs. Leaves alternate or spuriously whorled, exstipulate. Flowers hermaphrodite, axillary, usually crowded at nodes, more or less pedicellate. Sepals 5, equal, imbricated. Petals 0 or indefinite, entire or 2-3-fid. Stamens 8-20, distinct or in groups. Ovary superior, 3-5-celled, many-ovuled; styles 3-5. Capsule incompletely 3-5-celled, membranous, 2-5-grooved, opening by 5 valves. Seeds reniform, with an entire caruncle; embryo curved, cylindrical.