A two-year floristic survey of the 7,690-ha Pushmataha Wildlife Management Area (PWMA) located in the Kiamichi Mountains of southeastern Oklahoma revealed the known vascular flora to comprise 447 species in 287 genera and 97 families. The four largest families—Poaceae, Asteraceae, Fabaceae, and Cyperaceae—compose 43.4% of the flora. The largest genera are Carex, Juncus, Dichanthelium, Desmodium, and Lespedeza. Native species account for 92.8% of the taxa. Three introduced species appear to be naturalizing in the area: Elaeagnus angustifolia, Lespedeza cuneata, and Sorghum halepense. Thirteen species designated as rare by the Oklahoma Natural Heritage Inventory were encountered: Dulichium arundinaceum, Justicia ovata var. lanceolata, Brachyelytrum erectum, Calamovilfa arcuata, Piptochaetium avenaceum, Smilax smallii, Ilex opaca, Ribes cynosbati, Tilia americana var. caroliniana, Polygala polygama, Carex oxylepis, Carex oklahomensis, and Mitchella repens.