Annual or perennial (often marshy or aquatic) herbs, suffrutices, shrubs or trees. Stipules 0 or 2-10 or more, small, subulate, axillary. Leaves simple, entire, opposite and decussate, sometimes whorled. Flowers bisexual, actinomorphic or rarely zygomorphic (Cuphea), (3-)4-5(6-16)-merous, monomorphic or often dimorphic or trimorphic. Inflorescences various; pedicels usually with bracteoles. Calyx persistent. Petals 0 or as many as calyx lobes. Stamens variable in number, sometimes unequal. Ovary 2-6-locular. Fruit usually a capsule.