Systematics Section / ASPT
Joly, Simon , Starr, Julian R. , Bruneau, Anne .
How many Rosa species in eastern North America?
TAXONOMISTS have long been baffled by the complexity of Rosa. In North America and worldwide, the extensive morphological variation of species in the genus has greatly impaired species identification. Here we focus on native North American species of section Cinnamomeae (incl. Carolinae) that are found east of the Rocky Mountains. We used a multivariate approach with both quantitative morphological characters and genome-wide molecular markers (AFLP) in order to delimit the species boundaries. Among the diploids, this study supports the species status of R. foliolosa, R. nitida and R. palustris. In contrast, although together they are distinct from other diploid species, R. blanda and R. woodsii cannot be distinguished from one another and their status should therefore be reconsidered. At the polyploid level, the species status of R. arkansana is supported, but that of R. carolina and R. virginiana is more complex. These latter species are morphologically and genetically somewhat different but they do not form clearly distinct groups. Our analyses of nuclear genes and morphological characters suggest that R. arkansana has evolved from the group of R. blanda and R. woodsii. However, these data do not entirely resolve the question of the polyploid origin of R. carolina and R. virginiana. Morphologically each of these tetraploid taxa are equally similar to more than one diploid species, and the molecular data differ from the morphology as to which diploid is most similar to these polyploids. Regardless, the data tend to indicate that R. carolina and R. virginiana have different evolutionary histories.
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1 - Université de Montréal, Institut de recherche en biologie végétale, 4101 rue Sherbrooke est, Montréal, Québec, H1X 2B2, Canada
2 - University of Mississippi, Department of Biology, 214 Shoemaker Hall, University, Mississippi, 38677, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM