Hipp, Andrew L. , Weber, Jaime A. .
Species status and population genetic structure of a Great Lakes endemic oak, Quercus ellipsoidalis E.J. Hill (Fagaceae).
The Great Lakes endemic Hill’s oak (Quercus ellipsoidalis) is not readily distinguished from black oak (Quercus velutina) or scarlet oak (Quercus coccinea) in the upper Midwest. Our previous work has shown that the three species can be discriminated from one another using AFLP data and that the closest relationship among these species is between Q. velutina and Q. ellipsoidalis. In the current study, we expand our sampling to investigate population genetic structure within each species and admixture between species. Our research to date suggests three major findings. (1) Individuals form distinct genetic clusters by species, and weaker clusters by site or geographic region. The only strong phylogeographic split within species is replicated in Q. velutina and Q. coccinea and occurs between the Northeastern and Midwestern U.S. (2) There is more evidence of admixture between Q. velutina and Q. ellipsoidalis than between Q. velutina and Q. coccinea. The highest proportions of individuals exhibiting substantial admixture occur in Wisconsin populations and a northeastern Illinois population that was identified prior to the study as a potential Q. velutina – Q. ellipsoidalis hybrid zone based on field observations. (3) Despite the evidence for admixture, morphological species identification and molecular population assignment correlate well, as long as adequate material—mature buds, leaves and acorns—are available for morphological identification. This latter finding helps to settle long-standing questions about the taxonomy of the black oak group in the Chicago region.
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1 - The Morton Arboretum, 4100 Illinois Route 53, Lisle, IL, 60532-1293, USA
2 - The Morton Arboretum, Herbarium, 4100 Illinois Route 53, Lisle, IL, 60532-1293, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Lake Michigan/Hilton
Date: Tuesday, July 10th, 2007
Time: 2:15 PM