Trees, shrubs or herbs, the shrubs and herbs often twining. Leaves alternate or rarely opposite or whorled, mostly pinnate or pinnately, 3-foliolate or 1-foliolate or simple or palmate. Stipules present but sometimes very small or obsolete; stipellae sometimes present. Inflorescence consisting of terminal or axillary racemes or panicles, less often heads, spikes or clusters or flowers solitary. Flowers mostly hermaphrodite, zygomorphic. Receptacle campanulate, tubular or nearly wanting. Sepals usually 5, or 4, connate. Petals 5, imbricate, unequal, the adaxial exterior forming the standard (vexillum), the lateral pair forming the wings (alae) adhering to the keel or free, the abaxial inferior pair enclosing the stamens and style and often cohering by their lower margins to form the keel (carina). Stamens 10 or 9, monadelphous or diadelphous and then the vexillar stamen free, rarely all free; anthers uniform or unequal, 2-celled, dorsifixed or basifixed, opening by longitudinal dehiscence. Ovary superior, uni-locular; style simple; stigma small or capitate. Ovules 1 to numerous, anatropous. Fruit various, often a 2-valved pod or lomentum, rarely drupaceous. Seeds with a large embryo; endosperm few or wanting. Cotyledons foliaceous or thick-carnous. About 12000 species in 480 genera, in all parts of the world.