Graduation date: 1995Infrageneric classification in Ribes has previously relied on a few, often\ud conflicting, morphological markers, such as spines, glands, and inflorescence\ud morphology. Suggestions that hybridization drives the evolution of the genus have\ud not been tested using phylogenetic methods. To assess the validity of infrageneric\ud classifications and the importance of hybridization to the evolution of the group, and\ud to develop an explicit phylogenetic hypothesis, I surveyed exemplars from all\ud subgenera for restriction site variation in two cpDNA regions. Parsimony analysis\ud shows that red currants, European alpine currants, golden currants, true gooseberries,\ud and western gooseberries appear on separate clades. A less well supported Glade\ud includes the western North American ornamental currant group and a portion of the\ud dwarf currants. The presence of distinct lineages in Ribes is strongly supported by\ud characters with very high consistency, suggesting that hybridization among\ud infrageneric groups is not common in the genus. Unexpectedly, spiny currants and\ud true gooseberries are united, suggesting either a sister group relationship or the\ud possibility that one of these groups arose by reticulate evolution. The four black\ud currant species examined exhibit surprisingly high divergence, and are not\ud monophyletic in the analysis. Maximum likelihood analysis supports these results.\ud Basal relationships of these lineages are not well resolved.\ud A similar analysis of a portion of the nuclear ribosomal repeat produced very\ud few characters. Although these data are highly homoplasious, their analysis bears\ud some resemblance to that of the chloroplast DNA. Most prominently, the ornamental\ud currant Glade has identical membership.\ud Brief reviews of the scattered palynological and paleontological literature\ud concerning Ribes are presented
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