Emily Sessa

Patricia K. Holmgren Director, William and Lynda Steere Herbarium

Ph.D., University of Wisconsin–Madison


Ecology and Evolution of Ferns and Lycophytes



Systematics, phylogenetics, historical biogeography, diversification, reticulate evolution, community assembly

Research locations

Eastern North America, Africa



My research focuses broadly on plant systematics and evolution, and I am particularly interested in understanding the evolution of ferns and lycophytes. These two lineages have existed for hundreds of millions of years, and their members have survived major mass extinction events throughout Earth’s history and continue to play critical roles in modern ecosystems. My lab members and I work on a number of different topics to understand the ecology and evolution of these plants, including studying historical biogeography and diversification processes and the ecology of fern gametophytes.



Sessa Lab

Emily SessaTwitter


Selected Publications

  • Testo WL, AL de Gasper, S Molino, JM Gabriel y Gálan, A Salino, VA de Oliveira Dittrich, and EB Sessa. (2022) Deep vicariance and frequent transoceanic dispersal shape the evolutionary history of a globally distributed fern family. American Journal of Botany. doi: https://doi.org/10.1002/ajb2.16062 PDF
  • Marchant DB, G Chen, S Cai, J Jenkins, S Shu, C Plott, J Webber, J Lovell, G He, L Sandor, M Williams, S Rajasekar, A Healey, K Barry, Y Zhang, EB Sessa, PG Wolf, A Harkess, F-W Li, P Schafran, A Becker, L Gramzow, D Xue, Y Wu, F Chen, T Tong, Y Wang, F Dai, S Hua, H Wang, S Xu, F Xu, H Duan, G Theißen, RJ Schmitz, D Stevenson, B Ambrose, JA Banks, JH Leebens-Mack, J Grimwood, J Schmutz, PS Soltis, DE Soltis, and Z-H Chen. (2022) Ancient yet Dynamic: The Evolution of a Fern Genome. Nature Plants 8(9): 1038–1051. doi: https://doi.org/10.1038/s41477-022-01226-7 PDF
  • Karichu MJ, BK Ngarega, GE Onjalalaina, P Kamau, and EB Sessa. (2022) Ecological niche modeling predicts the potential distributions of African Azolla species and their implications for African wetland ecosystems. Ecology and Evolution 12(8): e9210. doi: https://doi.org/10.1002/ece3.9210 PDF
  • Pelosi JA, EH Kim, WB Barbazuk, and EB Sessa. Phylotranscriptomics illuminates the placement of whole genome duplications and gene retention in ferns. Frontiers in Plant Sciences 13: 882441. 23 pages. doi: https://doi.org/10.3389%2Ffpls.2022.882441 PDF
  • Pinson JB, SM Chambers, and EB Sessa. The spatial separation of Callistopteris baueriana (Hymenophyllaceae) sporophytes and gametophytes along elevation gradients on the island of Oahu, Hawai’i. American Fern Journal 112(1): 1–16. doi: https://doi.org/10.1640/0002-8444-112.1.1 PDF