Format: ORAL

Alejandra Vasco1 Weston Testo2

1 Botanical Research Institute of Texas, Fort Worth, USA 2 University of Vermont, Burlington, USA

The fern genus Elaphoglossum (Dryopteridaceae) is one of the most species-rich and taxonomically complex genera of ferns globally, with over 600 recognized species. Despite extensive taxonomic and systematic studies, numerous species groups within Elaphoglossum pose persistent taxonomic challenges and several key evolutionary relationships within the genus remain unresolved. This complexity highlights the significance of improving our understanding of Elaphoglossumdiversity, given its status as one of the most species-rich, dominant, and frequently collected vascular plant genera in many areas of tropical America, where approximately 500 species ofElaphoglossum occur. This presentation introduces the first phylogenomic study of Elaphoglossum, including a dataset of more than 230 accessions and target-capture data from around 300 nuclear loci. The resulting phylogenetic hypothesis is largely congruent with those reported previously, but with improved support and resolution, and the recovery of novel clades and previously unsampled taxa. Our phylogenomic analyses also show, for the first time, that reticulate evolution was important and prevalent during Elaphoglossum evolutionary history. Integration of our phylogenomic data with information derived from floristic inventories, herbarium specimens, and rigorous taxonomic studies enables a data-driven assessment of the current state of knowledge for Elaphoglossum. From this, we highlight persistent challenges hindering the study of Elaphoglossum today and identify priorities and research opportunities for future exploration and research of this and other highly diverse and taxonomically complex fern genera.