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Abstract Detail



Recent Topics Posters

Liu, Shih-Hui [1], Hoch, Peter [2], Raven, Peter H. [2], Barber, Janet C. [3].

Preliminary phylogeny and polyploid-associated distribution patterns in Ludwigia (Onagraceae).

Polyploidy, a major evolutionary force in angiosperms, has been important throughout the history of the group and may contribute to the competitive success of invasive plants. It is estimated that the majority of angiosperms have experienced polyploid speciation at some point in their history. Nevertheless, many questions remain and polyploid speciation is still the core of the mystery of plant evolution. The group that we have chosen for study is the cosmopolitan, warm-temperate to tropical wetland genus Ludwigia (Onagraceae), comprising 82 morphologically diverse species placed in 23 sections. The extensive polyploidy and wide biogeographic distribution of Ludwigia make it an ideal group in which to explore the evolutionary role of polyploid speciation. Our earlier phylogenetic study of Ludwigia demonstrated the monophyly of a large clade identified as the North Temperate Haplostemonous group, which includes 4 sections and 24 species. In this study, using both chloroplast and nuclear sequencing data, we extend our phylogenetic study in the remaining 19 sections and 58 species of the genus, especially taxa from Central and South America. We also assessed the strength of association among distributions and ploidy in these sections. Even though our preliminary phylogeny, which includes 28 species in 10 of these sections, shows low resolution along the backbone of the tree, our results indicate that two large sections (Oligospermum and Macrocarpon) and one monotypic section (Caryophylloidea) are monophyletic groups with well support. Moreover, three other large sections (Pterocaulon, Myrtocarpus, and Africana) do not appear to be monophyletic. More thorough sampling of these and the other sections will be needed to resolve their relationships more completely more completely.


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1 - Saint Louis University, Biology, 3507 Laclede Avenue, St. Louis, MO, 63103, USA
2 - Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166-0299, USA
3 - Saint Louis University, Department Of Biology, 3507 Laclede Avenue, St. Louis, MO, 63103, USA

Keywords:
Biogeography
Speciation
polyploidy
Ludwigia
Onagraceae.

Presentation Type: Recent Topics Poster
Session: P
Location: /
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PRT028
Abstract ID:1266
Candidate for Awards:None


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