Sympatric parallel diversification of major oak clades in the Americas and the origins of Mexican species diversity.

My research emphasizes woody plants, especially the systematics of Fagaceae (the oak family), Juglandaceae (the walnut family), and related wind-pollinated families of flowering plants (Fagales). Our lab uses DNA sequences to generate hypotheses of phylogenetic relationship for inferring morphological character evolution, analyzing patterns of biogeography, and testing species concepts. Students and postdocs have studied the systematics and diversification of the following angiosperm families: Acanthaceae, Nyctaginaceae, Zingiberaceae, Rhamnaceae, Montiaceae, Humiriaceae, Solanaceae, Convolvulaceae, Piperaceae, Ericaceae, and Dilleniaceae. Current research interests involve a range of evolutionary and ecological questions within the Fagaceae. For example, we have reinterpreted cupule evolution in the Fagaceae and calibrated the phylogeny for the American clades of Quercus. Ongoing collaborations with Andrew Hipp, John McVay, Andy Crowl, Antonio González-Rodríguez, and Jeannine Cavender-Bares seek to integrate phylogenetic data with phenotypic traits and functional genes to explain species distributions and to better understand the adaptive nature of introgression in the oaks. Other research interests include the phylogeography of eastern North American woody plants, and patterns of speciation via polyploidy in the true blueberries, Vaccinium section Cyanococcus (with Andy Crowl, Hamid Ashrafi, and Peter Fritsch).