Systematics Section / ASPT
Golden, Joanne L. , Achuff, Peter L. , Bain, John F .
Comparative analysis of molecular variation among disjunct populations of Cirsium scariosum in Canada.
Cirsium scariosum Nutt. is one of several native foliose thistle species in western Canada and NW United States. A disjunct population of C. scariosum also occurs on the Mingan Islands in Quebec. In past taxonomic treatments, the Mingan populations have been treated as a distinct species Cirsium minganense, based on differences in breeding systems and habitat preferences. This view is not supported by recent floras. In Canada, the status of C. scariosum is considered rare in the western provinces of Alberta and BC, and in Quebec. Sequence analysis of ITS, ETS and chloroplast (psbA-trnH) regions show little or no difference between eastern and western populations of C. scariosum and a related species, C. hookerianum. ISSR data reveal the presence of unique alleles in the Mingan populations of C. scariosum, and genetic distances between eastern and western C. scariosum are greater than those between western species. These results suggest that hybridization has resulted in the merging of western C. scariosum populations with related sympatric species and provide support for the recognition of eastern populations of C. scariosum as distinct.
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1 - University of Lethbridge, Biological Sciences, 4401 University Drive, Lethbridge, Alberta, T1K 3M4, Canada
2 - Parks Canada, Ecological Integrity Branch, Waterton Lakes National Park, Waterton Park, Alberta, T0K 2M0, Canada
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM