The leaves of Senegalia galpinii, the monkey thorn, grow solitary or in pairs at stem nodes; sometimes in groups of up to four, particularly on older wood. The bipinnate leaf has nine to fourteen pairs of pinnae curving downwards from the central leaf rachis. A leaf may be 16 cm long, counting both petiole and rachis. Each pinna may have 13 to 40 pairs of tiny, oblong leaflets or pinnules, rounded or oblique in shape and hairless.
In the picture these pinnules appear obovate with rounded tips. Leaves arrive annually on this deciduous tree in spring as temperatures rise. Two short-lived leafy bracts may be seen by the base of the petiole of a young leaf.
The dark, hooked spines that can inflict a fair amount of damage are visible in the photo among the leaves on the branchlets (Carr, 1976; Coates Palgrave, 2002).