It grows 5-18 m in height and is fire-resistant. The common names in English and Afrikaans refer to the very characteristic thorns, which are knobbed. The knobs, which are borne on the trunks and branches, are occasionally lacking in individual specimens. The leaves are double pinnately compound. The plants are deciduous and the trees are usually leafless for the duration of the winter and early spring. The leaf form is characteristic of this species. There are only 4 -6 leaflets per leaf and these are comparatively large with oblique (lopsided) bases. The rachis is recurved and bears small spines. New leaf growth is sometimes bright red.