Emily Sessa

T.A. for Vascular Flora of Wisconsin - Section 301   esessa@wisc.edu

Office Hours: by appointment 

301 Birge Hall, 265-5473 

My research interests generally involve phylogeny and physiology of the seed-free vascular plants, otherwise know as the ferns. My PhD dissertation research combines phylogenetic systematics and ecophysiology in a study of the fern genus Dryopteris. This large (ca. 250 species worldwide) genus includes 13 species in North America, which differ greatly in their habitats and morphologies. As with many fern genera, hybridization and polyploidy play a large role in the evolutionary history of Dryopteris. My research involves investigating the monophyly of the North American species and testing an existing hypothesis of reticulate evolution in the group; physiological studies will involve characterizing light regimes of the North American taxa, and comparing static and dynamic photosynthetic responses and hydraulic properties among species, with a focus on the polyploids and their diploid parents. Initial phylogenetic work supports the non-monophyly of the North American taxa, but provides strong support from both nuclear and chloroplast data sets for the reticulation hypothesis and existence of a “missing diploid” ancestor in the group.