Herbs, shrubs or trees, sometimes climbers. Leaves alternate, bipinnate or rarely pinnate. Stipules present, often modified as spines. Inflorescence capitate, spicate, umbellate or racemose, solitary or arranged in racemes, panicles or fascicles. Flowers actinomorphic, 4- or 5-merous, hermaphrodite or polygamous. Calyx usually with distinct tube, lobate or dentate, the lobes valvate or rarely imbricate. Petals free or more commonly united, valvate. Stamens as many as or twice as many as the petals or indefinite; filaments free or united into a tube at the base. Ovary superior, usually solitary, uni-locular. Ovules several. Fruit a pod, sometimes breaking into one-seeded joints. Seeds with or without endosperm. Over 1500 species in 40 genera in tropical and subtropical regions.