Format: ORAL

Emily B. Sessa1, Jessie A. Pelosi2, Susan Fawcett3, J. Gordon Burleigh2

1 William & Lynda Steere Herbarium, New York Botanical Garden, Bronx, NY, USA 2 Department of Biology, University of Florida, Gainesville, FL, USA 3 University & Jepson Herbaria, University of California, Berkeley, CA, USA

Ferns are the second largest group of vascular land plants, with ca. 10,000, species, and they are critical components of Earths biodiversity ferns can be found in nearly every type of ecosystem and habitat, from desert to rainforest. Ferns also occupy a pivotal evolutionary position as sister to the megadiverse seed plants, and they are thus the critical outgroup needed to understand the evolution of key seed plant features. Fern phylogenetics as a field has evolved considerably since the 1990s, when the first rbcL-based phylogenetic analyses of ferns were completed. Fern phylogenetics has presented researchers with a number of challenges, including the deep evolutionary history of the group and their propensity to undergo hybridization and whole genome duplication. We will present a phylogenomic approach to fern evolution, using the most highlyresolved nuclear dataset to date (targeting 408 loci),and with highly targeted taxonomic sampling (including nearly all fern families and genera). This dataset allows us to explore a range of outstanding questions in fern phylogenetics, including resolving recalcitrant nodes, and comparing results between our nuclear based trees and other recent large-scale fern phylogenies based on chloroplast loci.