Gillespie, Emily , Kron, Kathleen A. .
Phylogenetic Relationships and Historical Biogeography of Cassiope (Ericaceae).
The genus Cassiope (Ericaceae) includes as many as 17 species of small evergreen shrubs that inhabit alpine and subalpine areas at high latitude and elevation in the northern hemisphere. Superficially, members of the genus are morphologically similar. All Cassiope have very small leaves that are decussate and appressed to the stem. Flowers in this group tend to be small, solitary and bell-shaped, and are most commonly light pink to white. Several Cassiope have been discovered and named in just the last two decades, particularly in remote areas of mountainous China, and therefore little is known about the evolution of these plants. The current study represents the first attempt to determine phylogenetic relationships within Cassiope. Thirteen of the 17 recognized species of Cassiope were included in the study, representing all major elements of the distribution. Two nuclear DNA regions (nrITS and GBSS-1/waxy) and one chloroplast region (trnS-G intergenic spacer) were examined. Bayesian analysis of the three DNA regions resolve nearly all relationships with strong support. One clade was resolved with five Asian species (e.g. C. myosuroides, C. nana, C. pectinata). Another clade is comprised with several Asian species (e.g. C. fastigiata, C. dendrotricha) along with Russian (C. ericoides) and northwestern North American species (C. lycopodioides). A basal grade is comprised of North American taxa (C. mertensiana and C. tetragona). Dispersal-Vicariance (DIVA) analysis suggests that the ancestral distribution of the genus may be northwestern North America and/or northeastern Asia.
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1 - Wake Forest University, Department of Biology, PO Box 7325, 226 Winston Hall, Winston-Salem, North Carolina, 27109-7325, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood D/Snowbird Center
Date: Monday, July 27th, 2009
Time: 10:00 AM