Systematics Section / ASPT
Sears, Chris , Schoonmaker, Amanda , Whitton, J .
A web spun on the tree of life? The reticulate evolutionary history in Crepis barbigera (Lactuceae: Asteraceae) inferred from morphology and chloroplast DNA sequence data.
CREPIS L. (hawks-beard) is a large genus of ca. 200 species distributed in temperate regions worldwide. In their monograph of North American Crepis, Babcock and Stebbins recognized ten morphologically and cytologically similar species native to western North America that are distinguished from one another based on differences in morphology, ploidy, ecology, and biogeography. One of the species Babcock & Stebbins recognized, the polyploid C. barbigera, is thought to be an allopolyploid derivative of C. atrabarba, C. acuminata, and C. modocensis ssp. rostrata. The recent taxonomic status of C. barbigera has not been stable and is currently synonymized with C. atrabarba. The objectives of this study are to circumscribe C. barbigera from closely related taxa and to determine its parentage using morphology and cpDNA. In addition to the above taxa a fifth taxon, C. intermedia was included in the morphometric and cpDNA studies. The results of the morphometric study show that C. barbigera is a distinct taxon but it does not differ from C. intermedia based on the scored characters. Initial results of the cpDNA study show a complex relationship between C. atrabarba, C. barbigera and C. intermedia.
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1 - University of British Columbia, Botany Department, 3529-6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 3:45 PM