Systematics/Phytogeography / Taxonomie/ Section
Barber, Janet C. , Diazgranados, Mauricio , Hoch, Peter C. .
Molecular phylogeny of Ludwigia (Onagraceae) reconstructed from multiple nuclear and cpDNA markers.
Ludwigia is a diverse and ancient genus comprising 82 species in 23 sections. Fourteen of the sections are monotypic, and only three have more than five species. Nine sections are endemic to or centered in South/Central America, three in North America, four in Africa, three in Asia, two in the Paleotropics, and two are cosmopolitan. Strong molecular and morphological data place Ludwigia as sister to the rest of the Onagraceae, so understanding its phylogeny is crucial to understanding the family. We are reconstructing a phylogeny using multiple molecular markers (both nuclear and chloroplast) that will enable us to assess the validity of this highly fragmented classification, determine relationships among the sections and species, assess the roles of polyploidy and hybridization in the evolution and radiation of the genus, and determine which area harbors the most plesiomorphic section(s) and may represent an ancestral area, and how and when the genus radiated from there to other areas. Although recent monographs are available for some sections, the genus as a whole has never been revised thoroughly, and the only synopsis of the genus was published more than 50 years ago. There is an abundance of recent comparative morphological data available for Ludwigia from anatomy, palynology, embryology, and cytology, as well as a strong fossil record, all of which will be re-evaluated in light of a rigorous molecular phylogeny. In the past year, we have increased our sampling and have added a second nuclear marker (waxy) and several additional cpDNA regions to our data set. These data have improved both resolution and support for various clades and are moving us closer to our goal of enabling comparative analysis within Onagraceae.
Log in to add this item to your schedule
1 - Saint Louis University, Department of Biology, 3507 Laclede Avenue, St Louis, Missouri, 63103-2010, USA
2 - Saint Louis University, Department of Biology, 3507 Laclede Ave., Macelwane Lab 231, St. Louis, Missouri, 63103-2010, United States of America
3 - Missouri Botanical Garden, Po Box 299, St Louis, Missouri, 63166-0299, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Room 1/Woodward
Date: Monday, July 28th, 2008
Time: 11:00 AM