Open AccessIn the genus Solanum L. (Solanaceae), subgenus Leptostemonum (Dunal) Bitter, section Acanthophora Dunal has four representatives in the Flora of southern Africa region (South Africa. Lesotho, Swaziland, Namibia. Botswana), namely S. aculeatissimum Jacq.. S. capsicoides Allioni. S. mammosum L. (cultivated only) and S. viarum Dunal. Section Ton a Nees has two representatives in southern Africa, namely S. chnsotriclium Schltdl. (S. hispidum auctt. non Pers.) and S. ton um Sw.; both are naturalized weeds. Solanum capsicoides, S. viarum and S. torvum have not been listed before for southern Africa. All are introduced species native to the New World. Descriptions, discussions, illustrations and distribution maps of the naturalized species are presented, as well as keys to the species of both sections.