An updated estimate of intergeneric phylogenetic relationships in the Australian Vitaceae

Abstract

Previous molecular studies have suggested that the genus Cissus (Vitaceae) is not monophyletic. The majority of species are grouped, but four Australian taxa (Cissus antarctica Vent., Cissus hypoglauca A. Gray, Cissus oblonga (Benth.) Planch., and Cissus sterculiifolia (F. Muell. ex Benth.) Planch.) form a distinct clade and Cissus opaca has now been recognized as belonging to the genus Clematicissus (Clematicissus opaca (F. Muell.) Jackes & Rossetto). Here, we investigate relationships among the Australian Vitaceae by parsimony and Bayesian analysis of plastid trnL-trnF and nuclear internal transcribed spacer sequences and include a range of taxa that had not been previously investigated. We find no support for a close relationship between Nothocissus and the four distinct Australian Cissus, as suggested in previous morphology-based treatments. We find a robust sister relationship between Clematicissus and at least two southern American Cissus (Cissus tweediana (Baker) Planch. and Cissus striata Ruiz & Pav.), suggesting a possible origin from an ancient southern progenitor. Finally, this study confirms the paraphyletic nature of Cayratia, with species occurring in two clades, both with Australian and non-Australian species. The necessity in future studies for data from additional and more tractable nuclear loci is also noted.