A systematic study of the genus rhoicissus planch, (vitaceae) in KwaZulu-Natal.

Abstract

The family Vitaceae, sometimes referred to as the grape family, comprises about 700 to 800 species and 13 to 14 genera, which includes Rhoicissus Planch. Rhoicissus contains 12 species all of which are described as climbing shrubs with tendrils that are without adhesive discs. This study was aimed at updating the taxonomy of the genus Rhoicissus in KwaZulu-Natal such that the names and number of species contained within the genus reflect the current findings. This dissertation looks primarily at the taxonomy of the leaves of the Rhocissus species of KwaZulu-Natal. The reason for this is that this work is meant to help conservationists, environmental managers, rangers, amateur botanists and others who will usually only encounters these species in their vegetative state. It is at this audience that this dissertation is aimed. Rhoicissus tridentata was found to be a complex that is made up of three subspecies: R. tridentata subsp. cuneifolia; R. tridentata subsp. diplonervia and R. tridentata subsp. tridentata. Phenetic results, scatter plots and polygonal graphs did not all support the division of R. digitata into three subspecies. Morphological results, however, did show the slight differences between the subspecies of R. digitata which are R. digitata subsp. digitata; R. digitata subsp. oravivens and R. digitata subsp. emarginata. The other species of Rhoicissus (R. revoilii; R. rhomboidea; R. sessilifolia and R. tomentosa) were all found to be distinct species.