Systematics Section / ASPT
Raveill, Jay A. , Farr, Danielle , Nikaido, Selene .
Chloroplast DNA phylogeny of eastern North American Desmodium (Fabaceae).
The genus Desmodium Desvaux (Fabaceae) occurs nearly world-wide and consists of over 300 species with 27 species native to eastern North America. A morphologically-based infrageneric classification placed the species into two sections. One section contained three species that were noted as highly diverged and a segregate genus, Hylodesmum Ohashi and R.R. Mill, has recently been proposed to include these species as well as 11 Asian species. The other section was further divided into 4 series based on flower size, fruit shape, and stipules. An initial effort to establishing a molecular-based phylogeny of the group has examined the trnL-trnF region of the chloroplast genome including an intron and an intergenic spacer. Nineteen samples representing 15 species were sequenced including two species, D. glutinosum and D. nudiflorum, of the three species from the possible segregate genus. The aligned sequences (1101 base pairs long) contained 89 polymorphic sites with regions of variable repeat numbers were counted as single sites. All variation occurred in noncoding sequence. Thirty-three sites were autapomorphic and not phylogenetically informative. A phylogeny was constructed using PAUP. An unrooted tree showed the two species included in Hylodesmum closely related to each other with a long branch to the remaining species. This clade was distinguished by 47 sites with 100% bootstrap support. These data provide further evidence for the segregation of Hylodesmum from Desmodium. The remaining sequences were closely related with only seven phylogenetically informative sites that provided little resolution.
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1 - Central Missouri State University, Department of Biology and Earth Science, Warrensburg, Missouri, 64093, USA
Presentation Type: Oral Paper
Location: Salon G - Austin Grand Ballroom/Hilton
Date: Wednesday, August 17th, 2005
Time: 9:15 AM