Systematics Section / ASPT
Redden, Karen M. , Herendeen, Patrick S. .
Morphological and molecular phylogeny of Elizabetha, Heterostemon, Paloue, and Paloveopsis (Leguminosae, Caesalpinioideae) from northeastern South America.
MOST phylogenetic work within the subfamily Caesalpinioideae concentrates on higher level relationships among the tribes, subtribes, and genus groups. Within Detarieae, Heterostemon (7 spp.), Elizabetha (10 spp.), Paloue (4 spp.) and Paloveopsis (1 sp.) are members of the Brownea clade that are endemic to northeastern South America. As recognized by Cowan in 1957, conflicting patterns of character distributions among these genera have presented difficulties for generic delimitation. His 1976 revisions of Elizabetha and Heterostemon were limited by the availability of some of the more problematic species and he recognized the possibility that these genera may need to be reorganized, rearranged or merged. Recent collections and field observations have enabled a closer morphological examination of the species as well as material for DNA sequencing. This study uses combined morphological and molecular data to explore generic limits and relationships among these genera and species. The data set includes 175 morphological and anatomical characters from vegetative and reproductive structures for all species and ITS and trnL intron sequence data for most species. This phylogeny is the culmination of my dissertation thesis and the basis for the reorganization of this group of species. Results of the morphological and combined morphological and molecular analysis are used to revise the generic and species limits of this group of closely related taxa. Morphological characters that were used to delineate the current generic boundaries are reevaluated and new characters are defined for generic and species identification. Patterns of morphological evolution, including flower structure and leaf form, will be examined based on the inferred phylogeny.
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1 - George Washington University, Department of Biological Sciences, Lisner Hall 340, 2023 G Street, NW, Washington, DC, 20052, USA
2 - George Washington University, Biological Sciences, 2023 G St.NW, Washington, DC, 20052, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 31st, 2006
Time: 4:00 PM