Acacia tortilis is a tropical spiny legume tree that grows to 12-21 m in height. It has a spreading and dense umbrella-shaped crown. The bole is more or less short and cylindrical, the crown is umbrella-shaped, spreading and somewhat dense.
His bark is slightly cracked to fissured, brown, slash pinky-brown, with dark brown outerbark. Stems are reddish to blackish purple, more or less glabrous or puberulous. Thorns are mostly straight, up to 5-10cm long, and the others are more or less curved, reaching 0.5cm long, set pairs in the leaf axil, white.
Leaves are alternate, bipinnate, up to 2.5-4.5 cm long, with 2-10 pairs of pinnae and 6-20 pairs of leaflets per pinna. Leaflets are oblong, glabrous or more or less pubescent, 3-4mm long and 0.5-1mm across. Petioles are 2-4 cm long, often with a crateriform gland above before the first pair of pinnae and sometimes others.
The flowering happened in the rainy season after the first leaves appear. The inflorescence is a fascicle, set in the leaf axil, composed of 1-6 glomerules, about 2.5cm long, whitish, pedunculate, 0.5-1cm in diameter. Fruits are pods more or less coiled into a spiral, 7-12cm long and 0.5-0.7cm across, pale green to yellowish when ripe, containing up to 10 seeds. Seeds are brown, more or less convex, elliptic or round, 4-7mm in diameter (Arbonnier, 2004).
