Trees or shrubs; leaves bipinnate or reduced to phyllodes, rarely absent; stipules 2, situated at base of phyllodes, caducous or persistent, small, scarious or sometimes spiny. <P>Inflorescences pedunculate, or sessile, globose heads, cylindric spikes or racemes, axillary and solitary or fasciculate or paniculate at the ends of the branches; flowers small, numerous in the heads, regular, normally hermaphrodite, bright golden-yellow to pale creamy white; sepals and petals 4 or 5, free or united; stamens numerous, exserted, free, inserted under or just above base of ovary; style filiform, exceeding the stamens; ovary sessile or stipitate, glabrous or puberulous, ovules numerous; bracteoles subtending each flower small, brownish, spathulate or peltate, claws linear. <P>Fruits legumes, linear to oblong, flat to terete, straight to curved or spirally twisted, chartaceous to woody, usually dehiscent; seeds oblong, almost orbicular or compressed-ovate, longitudinal or transverse in legume with a filiform funicle variously folded or encircling the seed and forming an aril.