preliminary numerical analysis of the red oak complex in Michigan and Wisconsin

Individuals representing five taxa and numerous unidentified OTU's of red oaks native to the western Great Lakes region of the United States were examined through principal components analysis. Two data sets, one consisting of twenty untransformed characters and one in which various characters were redefined as ratios, were employed for comparative analyses. Although minor differences are noted, the two data sets provide essentially the same view of the relationships between the included OTU's. The five taxa appear to form more or less discrete groups with the unidentified OTU's occupying positions of intermediacy. The results support previous conclusions that extensive hybridization occurs among the red oaks of this geographic region.