Systematics Section / ASPT
Hipp, Andrew L. , Weber, Jaime A. , Schlismann, Jason E. .
Identifying Hillís oak (Quercus ellipsoidalis), black oak (Q. velutina), and scarlet oak (Q. coccinea) in Northeastern Illinois.
Recent molecular investigations of Quercus ellipsoidalis (Hillís oak), Q. velutina (black oak), and Q. coccinea (scarlet oak) provide a useful context for identifying these taxa in the upper Midwest (Hipp and Weber, in review). In light of this molecular work, we have inspected all herbarium specimens for the Chicago metropolitan region from F, MOR, and CHIC and present a revised distribution map for these species in northeastern Illinois. The major findings are that (1) Q. coccinea is highly limited in distribution in northeastern Illinois, (2) the morphological range of Q. ellipsoidalis encompasses some of the variation typically ascribed to Q. coccinea, but that (3) Q. ellipsoidalis and Q. coccinea are nonetheless distinguishable from each other in northeastern Illinois. We recommend discontinued use of the name Q. coccinea for Chicago region populations of Q. ellipsoidalis. There continues to be difficulty in distinguishing Q. ellipsoidalis from Q. velutina, which is expected given our previous finding that there is some genetic admixture between these two. However, some of the difficulty in identifying these plants may be due to a misunderstanding of the morphological characters that define them. Ongoing scanning electron microscope (SEM) study of acorn pubescence clarifies a valuable character for identifying Q. ellipsoidalis and Q. velutina.
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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
3 - The Morton Arboretum, Herbarium, 4100 Illinois Route 53, Lisle, IL, 60532-1293
Great Lakes region
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM