Searsia undulata is a very variable species, ranging from low-growing shrubs to small trees according to the demands of different climates and soil types occurring in the plants natural distribution range. The leaf size also varies considerably, associated with similar causes.
Searsia is the name recently given to what used to be known as the Rhus genus, part of the Anacardiaceae or mango family. In Afrikaans these are known as karee trees or taaibos shrubs. There is almost surely a karee or taaibos species in your area in South Africa, bearing trifoliolate leaves.