Armed, glabrous shrubs or low tree, up to 4-6 m tall; branches tomentose, spinous, woody, drooping; leaves bipinnate, primary rachis, ending in long, stout spine; pinnae or secondary rachis, 2-3 pairs, long, striate, flattened like phyllodes; leaflets, minute 40-50 pairs, subopposite, oblanceolate, entire, obtuse; stipules spinescent; flowers few or many in axillary or terminal, lax racemes, shorter than the leaves; calyx deeply cleft, tube short, lobes 5, lanceolate, subequal, valvate, with subbasal disk; petals 5, yellow, exserted, obovate to suborbicular, subequal, claw short, very long in upper one; stamens 10, free, included, villous, filaments subequal, anthers versatile; ovary sessile or subsessile, many ovuled, style filiform; pods 5-10 cm long, flat, copper brown in colour, moniliform or slightly constricted between seeds, turgid, dry, dehiscent, narrowly winged on both sutures; seeds 3-6, compressed, brown.