The work presented in this thesis comprises two parts. The first part is a floristic survey of three tracts of the Ozark Plateau National Wildlife Refuge located in the Boston Mountains ecoregion in Adair County. The second part is a taxonomic treatment of the genus Quercus in Oklahoma which is to be incorporated in the forthcoming Flora of Oklahoma. Results of these studies are summarized in the following paragraphs. In a three-year (2007-2009) inventory of the Gittin Down Mountain, Liver and Varmint tracts of the Ozark Plateau National Wildlife Refuge in Adair County, Oklahoma, 392 species in 275 genera and 85 families were encountered. Three hundred sixty (91.8%) of the species were native to North America. Constituting 23.6% of the flora, the Asteraceae and Poaceae were the largest families. Quercus, Carex, Desmondium, and Dichanthelium were the largest genera present. Eighty-two species were new records for Adair County. Species designated threatened or endangered by The Endangered Species Program of the United States Fish & Wildlife Service were not discovered. Thirteen species designated rare (S1 or S2) by the Oklahoma Natural Heritage Inventory were documented as present. Herbarium and field studies conducted from 2006 to 2009 revealed that the oak (Quercus) flora of Oklahoma comprises 24 species, 3 varieties, 4 named hybrids and numerous putative hybrid individuals. Sixty-five morphological characters were examined and scored in order to generate taxon descriptions. The range of variation for each character exhibited by Oklahoma individuals was determined and incorporated in the species descriptions. Nomenclatural, taxonomic, and ecological notes were added as appropriate to complement the morphological descriptions. A dichotomous key for the identification of the 24 species and 4 named hybrids was constructed.Department of Botan
