Theodore Lee Esslinger
Theodore Lee Esslinger is an American lichenologist and former professor of botany. He is best known for his systematic work on the brown lichens and for developing online resources for lichen taxonomy.
Career
Esslinger studied at Eastern Washington University, the University of Idaho, and Duke University, where he completed his PhD in 1975 under William and Chicita Culberson. His dissertation, titled A Chemosystematic Revision of the Brown Parmeliae, focused on the chemical and morphological variation within the group. After a postdoctoral year at the Smithsonian Institution with Mason Hale, he joined the faculty at North Dakota State University in Fargo, where he has taught botany since 1975. As of 2025, he is listed as an emeritus professor at NDSU.He has published extensively on the taxonomy of parmelioid lichens, the family Physciaceae, and the genus Oropogon. From 1991 to 2006, he maintained the influential online bibliography Recent literature on lichens, which compiled and indexed lichenological publications worldwide. He served as president of the American Bryological and Lichenological Society from 2007 to 2009.