Sweeney, Patrick .
Phylogenetic relationships of Garcinia L. (Clusiaceae) and relatives with an emphasis on understanding patterns of floral evolution.
THE pantropically distributed dioecious tree genus Garcinia (Clusiaceae), which includes the delectable mangosteen, has centers of diversity in southeast Asia and Madagascar. The genus is comprised of over 250 species (when broadly circumscribed to include the segregate genera Pentaphalangium, Rheedia, and Tripetalum) and is remarkable for its extreme floral diversity. The flowers show variation in number of flower parts, amount of fusion within and between organs, the shape and number of anther sacs, and the presence or absence of sterile reproductive organs - indeed, the morphological nature of some structures is unclear. Previous sectional-level classifications have relied heavily on floral morphology when circumscribing sub-generic taxa. To test the monophyly of the genus and to infer relationships among a broad sample of Garcinia, I use parsimony and likelihood techniques to analyze sequence data from two nuclear genes, granule-bound starch synthase (GBSSI or waxy) and the internal transcribed spacer (ITS). These analyses support the monophyly of Garcinia (including Pentaphalangium, Rheedia, and Tripetalum) as well as many of the previously circumscribed taxonomic sections. Optimizations of floral traits on the Garcinia phylogeny suggest that while many floral features are synapomorphies for large groups of species, other features may have arisen in parallel.
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1 - University of Missouri - St. Louis, Biology Department, One University Blvd, St. Louis, Missouri, 63121, USA
Presentation Type: Array
Date: Monday, July 31st, 2006
Time: 2:00 PM