Yang, Ya , Morden, Clifford W. , Sack, Lawren , Sporck, Maggie J. , Berry, Paul E. .
Phylogeny and adaptive radiation of woody Hawaiian Chamaesyce from herbaceous and annual ancestors in subtropical North America (Euphorbia-Euphorbiaceae).
The Chamaesyce clade is a cosmopolitan plant group with over 300 species nested in the genus Euphorbia (Euphorbiaceae). Most members of the clade are small herbs that exhibit C4 photosynthesis. As such, they are typically adapted to dry, warm and exposed habitats, and many species are weedy. In contrast, there are 27 recognized woody Chamaesyce taxa that have radiated throughout all of the main Hawaiian Islands. Surprisingly, C4 photosynthesis is still found in all Hawaiian Chamaesyce, including shrub and tree taxa up to nine meters tall, among the largest C4 plants in the world. These exceptional C4 plants are under active study in their physiological adaptations and conservation, especially as many of the species are rare, with seven federally listed as endangered. We are attempting to provide a well-resolved phylogeny of the Hawaiian Chamaesyce clade to assist physiological and conservation studies. Molecular phylogeny using ITS, trnL-F, trnH-psbA, ndhA intron and nuclear low copy gene deadx9 reveals a complex evolutionary history among the Hawaiian taxa. Comprehensive taxon sampling from Chamaesyce worldwide shows the most closely related non-Hawaiian Chamaesyce species most likely belong to a clade of four weedy and annual Chamaesyce species found in warm and dry areas of Mexico.
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1 - University of Michigan, Ecology and Evolutionary Biology, 2037 Kraus Natural Science Building, 830 North University Ave., Ann Arbor, MI, 48109-1048, United States
2 - University of Hawaii, Botany Department, 3190 Maile Way, Honolulu, HI, 96822, USA
3 - University of California, Los Angeles, Ecology and Evolutionary Biology, 621 Charles E. Young Drive, Los Angeles, CA, 90095, USA
4 - University of Hawaii, Manoa, Department of Botany, Ecology, Evolution and Conservation Biology, 3190 Maile Way, St. John 101, Honolulu, HI, 96822
5 - University of Michigan, EEB Department and Herbarium, 830 N University, Ann Arbor, MI, 48105, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Maybird/Cliff Lodge - Level C
Date: Wednesday, July 29th, 2009
Time: 10:30 AM