Research in the Sessa lab focuses broadly on plant systematics and understanding the evolutionary and ecological processes that shape plant diversity. Lab members work on a number of projects around this central theme, with phylogenetics as the unifying conceptual framework. Phylogenies frame our research in a number of related areas, including: basic understanding of relationships among taxa, reticulate evolution, diversification rates and biogeographic history of organisms, community phylogenetics, and trait evolution using comparative methods. Organismally, we have a strong focus on the seed-free vascular plants: ferns and lycophytes. Our work, whether on ferns and lycophytes or other systems, depends on data collected via field and experimental studies and Sanger and next-generation sequencing. We integrate techniques from several disciplines, including computational and evolutionary genomics, phylogenetic systematics, physiological ecology, and traditional specimen-based botany. There are many ongoing projects in the lab, including those listed below.