Vachellia robusta subsp. robusta flowers at Silkaatsnek

The leaflets of Vachellia robusta subsp. robusta, the brack thorn or enkeldoring in Afrikaans, are dark green above, paler below. They are spaced along the rachis, the connecting stalk, with variable numbers of leaflets developing. There are glands present on the rachis near the first or last pairs of leaflets.

The flowers are creamy white spheres that appear at the end of winter and in spring. Leaves and blooms arrive together.

The fruit pods may be 15 cm long, 3 cm wide and almost straight. The pods are yellow, grey or brown and not constricted between the seeds as is the case in several other Vachellia species.

There is inconsistency in the release of the seeds, i.e. some pods may stay shut and fall to the ground before they open (Coates Palgrave, 2002; Van Wyk and Van Wyk, 1997).