Scott, Randy , Similes, Barbara , Ayers, Tina .
The status of Brickellia knappiana E. C. Drew and its implications for the B. californica-B. desertorum complex.
Brickellia knappiana has been suggested to be a possible hybrid derived from a cross between B. multiflora (= B. longifolia var. multiflora (Kellogg ) Cronquist) and B. desertorum Cov. and/or B. californica A. Gray where the ranges of these species overlap. Recent floristic treatments have maintained B. knappiana as a distinct species in the absence of definitive studies. Field work coupled with morphometric studies and the analysis of sequence data from cpDNA (atpB-rbcL spacer region) and nr ITS DNA confirm that one known population of B. knappiana at Crystal Springs in the Kingston Range of the eastern Mojave is of hybrid origin. Preliminary AFLP data corraborate this finding. The two parental species at this site are B. desertorum and B. longifolia S. Watson. Despite extensive field work using localities from herbarium vouchers, no further populations of B. knappiana have been found suggesting that this taxon is an ephemeral hybrid. Hybrids between B. californica and B. longifolia have not been observed in other parts of their ranges where they overlap. Sequence data from a range of populations also suggest that B. desertorum is genetically distinct from B. californica despite considerable overlap in their morphology where their distributions overlap. Further field work and genetic studies are underway to clarify the highly variable B. californica complex.
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1 - Northern Arizona University, Department of Biological Sciences, P.O. Box 5640, Flagstaff, Arizona, 86011-5640, USA
ITS sequence data
plastid sequence data.
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood D/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 3:45 PM