Article An Updated Infrageneric Classification of the North American Oaks (Quercus Subgenus Quercus): Review of the Contribution of Phylogenomic Data to Biogeography and Species Diversity Paul S. Manos 1,* and Andrew L. Hipp 2 1 Department of Biology, Duke University, 330 Bio Sci Bldg, Durham, NC 27708, USA 2 The Morton Arboretum, Center for Tree Science, 4100 Illinois 53, Lisle, IL 60532, USA;
[email protected] * Correspondence:
[email protected] Abstract: The oak flora of North America north of Mexico is both phylogenetically diverse and species-rich, including 92 species placed in five sections of subgenus Quercus, the oak clade centered on the Americas. Despite phylogenetic and taxonomic progress on the genus over the past 45 years, classification of species at the subsectional level remains unchanged since the early treatments by WL Trelease, AA Camus, and CH Muller. In recent work, we used a RAD-seq based phylogeny including 250 species sampled from throughout the Americas and Eurasia to reconstruct the timing and biogeography of the North American oak radiation. This work demonstrates that the North American oak flora comprises mostly regional species radiations with limited phylogenetic affinities to Mexican clades, and two sister group connections to Eurasia. Using this framework, we describe the regional patterns of oak diversity within North America and formally classify 62 species into nine major North American subsections within sections Lobatae (the red oaks) and Quercus (the Citation: Manos, P.S.; Hipp, A.L. An Quercus Updated Infrageneric Classification white oaks), the two largest sections of subgenus . We also distill emerging evolutionary and of the North American Oaks (Quercus biogeographic patterns based on the impact of phylogenomic data on the systematics of multiple Subgenus Quercus): Review of the species complexes and instances of hybridization.