A new species of Putterlickia (Celastraceae) from southern Natal and Pondoland

Putterlickia retrospinosa Van Wyk & Mostert, a woody forest climber endemic to the sandstone region of southern Natal/Pondoland is described. It is allied to P. verrucosa (E. Mey. ex Sond.) Szyszyl. from which it differs in its exclusively climbing habit, reflexed spines, much larger leaves which are broadly elliptic to broadly obovate with entire margins, and relatively large inflorescences. Hitherto the genus Putterlickia Endl. has been characterized by up to six ovules per locule. The new species usually has 8 – 10 ovules per locule. Up to 8(–10) ovules were also occasionally recorded in the other species. Although the geographical distribution of P. retrospinosa falls within the range of P. verrucosa, the two species are mutually exclusive with the latter not transgressing onto the sandstone. No evidence of clinal variation or introgression between these two species was found