Trees, shrubs or climbers. Leaves alternate, simple, usually consisting of two lobes or almost bifoliolate with midrib between the two leaflets produced as a small spur. Flowers are showy, arranged in simple or panicled, terminal or axillary racemes. Hypanthium sometimes long and cylindrical, sometimes short and turbinate. Calyx entire or spathaceous, or cleft into two or five teeth. Petals 5, slightly unequal, narrowed at the base into a claw, variously coloured. Stamens 10, or reduced to 5 or there, filaments free or shortly connate, filiform, anthers versatile, Dehiscing longitudinally. Ovary seated on a stalk (gynophore), ovules many, style long or short and usually curved, stigma capitate, fruit a linear pod, dehiscent or indehiscent.
A genus with c. 570 species, mostly distributed in tropics and warm temperate regions of both the hemispheres.