| This study examined the phylogenetic relationships among species of Turiiera by using the internal transcribed spacer region as a molecular marker. Species of Piriqueta, a closely related genus to Turnera, were used as an outgroup to root all phylogenetic trees. The resulting trees were used to assess base chromosome number, breeding system, and polyploid evolution. In order to resolve the origins of allopolyploidy, it was necessary to isolate homeologous ITS regions within the allopolyploid species.;Resolution of the available series of Turnera was accomplished. The Capitatae are basal within Turnera. T. sidoides requires series reclassification, possibly as a new series. The Papilliferae appear to have evolved from the Microphyllae; if so these species should be included within the Microphyllae. The Salicifoliae are paraphyletic, and may require series reclassification. Both the Leiocarpae and series Turnera are well-supported groups. A base chromosome number of x = 7 was the ancestral condition within Turnera, subsequently giving rise to x = 13 in the Papilliferae and x = 5 in series Turnera.;It was not possible to fully resolve the origins of allopolyploidy within series Turnera. (Abstract shortened by UMI.)... |
