UBC Theses and Dissertations
The systematics of Rocky Mountain Maple, Acer Glabrum Torr Justice, Douglas Edward Clive
This study was undertaken to determine the most appropriate infraspecific taxonomy for Acer glabrum, as a review of the recent literature showed that the biological and taxonomic validity of the infraspecific taxa of Acer glabrum is not clear. This study involved field and herbarium studies, morphometric analysis, common garden transplant experiments and foliar flavonoid analysis. Field and herbarium studies showed that subsp. siskiyouense, var. greenei and var. tripartitum, names common in the literature, do not represent valid taxa. Varieties diffusum, douglasii, glabrum, neomexicanum, and torreyi are recognized, and have distinguishing leaf morphological characters that are correlated with more or less discrete geographical ranges. Morphometric analysis showed that leaf morphology is geographically correlated, but some numerical methods are not able to discriminate all taxa. Transplant experiments suggest that the distinctive morphologies of the early leaves of individual taxa are genetically fixed, and that late leaves, subject to environmental constraints, all tend toward a single morphology. Flavonoid analysis showed that there is no variation within or among the infraspecific taxa. The presence of flavanones strengthens the presumed close relationships between sections Glabra, Arguta, Cissifolia and Indivisa.
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