Low perennial herbs or undershrubs. Lvs. opposite, entire, subsessile, exstipulate. Fls. bisexual, regular, small, solitary or in cymes. Sepals 4-6, persistent, connate, tubular. Petals as many, clawed, imbricate, with scalelike appendage within. Stamens usually 6, hypogynous. Ovary superior, 1-celled, with 2-4 parietal placentae and few to many ovules. Fr. a caps, opening by valves. Seeds with endosperm and straight embryo. Four genera and about 65 species, widely distributed in subtrop. and temp. regions. (Munz, Flora So Calif. 484).