Systematics/Phytogeography / Taxonomie/ Section
Marx, Hannah , Lu-Irving, Patricia , Olmstead, Richard .
Phylogeny and Evolution of the Verbenaceae s.s.: Evidence from Chloroplast and Nuclear DNA Sequences.
Historically, the Verbenaceae has been a large and poorly defined group due to the wide range of morphological characters and geographical distribution of its members. Previous studies have relocated many genera of the traditionally recognized Vebenaceae to the Lamiaceae, and redefined the Verbenaceae s.s. as a smaller monophyletic group comprising 4-7 tribes with c.a. 34 genera and 1200 species. Our goals are to use data from both chloroplast and nuclear genomes to investigate the monophyly of tribes circumscribed by morphological characters, to identify major clades within the family, and to determine biogeographical patterns. Verbenaceae s.s. includes small forest trees, shrubs, herbs, and lianas. They are predominantly found in the New World, with a few groups in Africa and Madagascar, and occur in habitats ranging from wet tropical forests to temperate deserts and high Andean ecosystems. Using field-collected leaf tissue as well as herbarium specimens from around the world, we have produced a detailed molecular phylogeny of the Verbenaceae s.s. We have included 83 taxa representing 32 genera with data from ndhF and trnL-F of the chloroplast genome and the nuclear gene waxy. Here we present a phylogeny of the Verbenaceae, revealing the polyphyletic relationships of traditionally circumscribed tribes. Resolving the species level relationships between members of recently radiated groups within the Verbenaceae is problematic due to the short branch lengths separating these taxa. For species rich clades such as the Lippia-Lantana complex, we are investigating different chloroplast and nuclear markers that will be used to clarify these more intricate relationships. For tribes that are not monophyletic, we present suggestions for classification. Finally, we discuss how our data explain the migration from South America into the Northern Hemisphere and the colonization of Africa.
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1 - University of Washington, Department of Biology, Box 355325, Seattle, WA, 98195, USA
2 - University of Washington, Department of Biology, Box 355325, Seattle, Washington, 98195-5325, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, July 30th, 2008
Time: 10:00 AM