My primary research focuses on changes in the vegetation occurring during the Late Paleozoic Ice Age, specifically the latest Pennsylvanian through the Early Permian (~310-275 million years ago) of Oklahoma and Kansas. My students and I are investigating the palynology—pollen and spores—of core and outcrop samples collected in southwest and north-central Oklahoma to establish the timing and magnitude of the shift from “humid-adapted” vegetation of the Pennsylvanian to “arid-adapted” vegetation of Permian. I am also interested in the diversification of heterosporous ferns that coincided with the Cretaceous expansion of flowering plants. Combining analyses of specimens from the Atlantic and Gulf Coastal plains using scanning electron microscopy with database compilations, details of their taxonomic and morphologic diversification are emerging. And I am working with graduate students on the taxonomy and anatomy of petrified wood floras from the Morrison Formation of Oklahoma, Utah, and Montana to understand local Late Jurassic paleoecology and climate.
