Herbs, sometimes becoming woody. Leaves simple; stipules absent. Flowers regular, bisexual. Floral tube often extending above the ovary. Sepals 4–5, valvate. Petals 4–5, imbricate, twisted in the bud. Stamens usually twice as many as the petals. Ovary inferior, 4–5-locular; placentas axile; style capitate or lobed. Fruit usually a capsule, opening from the summit. Seeds few to numerous. 22 gen., temp. to subtrop., mostly America.