Mushroom Hunter: Dr. Dennis E. Desjardin

Dennis Edmund Desjardin (1950-current) is an American mycologist who has been called the "Mushroom Guru of the West Coast". He was born in Crescent City, California and started his life's work at the age of three, collecting mushrooms with his grandparents. He attended San Jose State University for a time but dropped out to play jazz professionally.

A decade later, he attended San Francisco State University and graduated in 1983 with a B.S. in botany, and in 1985 with an M.A in ecology and systematic biology. His M.A. thesis (The marasmioid fungi of California) was supervised by Harry D. Thiers (see Mushroom Hunter: Dr. H. D. Thiers). Desjardin attended the University of Tennessee and graduated in 1989 with a Ph.D. in mycology. His Ph.D. thesis (The genus Marasmius from the southern Appalachian Mountains) was supervised by Ronald H. Petersen.

Dr. Dennis E. Desjardin (photo from the California Mushrooms website)

Desjardin worked as an assistant professor at a small liberal arts college in Ohio, and then worked his way up to a full professorship at San Francisco State University, where he worked until his retirement. He researched mycology in California and around the world, funded by numerous National Science Foundation grants. He conducted field studies and documented fungal diversity and the ethnomycology of indigenous cultures. He is the author or coauthor of over 150 scientific publications. He was appointed the director of SFSU's Harry D. Thiers Herbarium, and served as an associate editor for Fungal Diversity and Mycologia.

Dr. Desjardin spent 40 years documenting California's mushrooms, and coauthored California Mushrooms: The Comprehensive Identification Guide. He also researched ecology and the biogeography of fungal species associated with tropical and island habitats, bioluminescent fungi, and fungal systematics. He coauthored "Mushrooms of Hawai'i: An Identification Guide".  Desjardin discovered or co-discovered more than 300 fungal species, including species of luminescent mushrooms. Several mushrooms are named after him, including Agaricus desjardinii, Marasmius desjardinii, and Arcangeliella desjardinii. He retired from SFSU in 2021 and left academia to start a new career at Sempera as Chief Mycologist.

Dr. Desjardin (photo from the Sempera Organics website) 

I was interested to learn more about Dr. Desjardin because of his specialization in Californian mushrooms, and his interest in fungi around the world. I especially enjoyed reading about the naming of the SpongeBob SquarePants mushroom (Spongiforma squarepantsii). It's always a joy to see scientists having some fun! I also appreciated hearing that Dr. Thiers had named Gastrolactarius desjardinii to honor his colleague/protege.

Note: mushrooms are  renamed and reclassified continually as new information is discovered.

Learn More

• California Mushrooms website, which promotes California Mushrooms: The Comprehensive Identification Guide by Dennis E. Desjardin, Michael G. Wood, and Frederick A. Stevens. Select the About and Bios tabs for information about the book and its authors. https://www.californiamushrooms.us/index.html

An online version of the book is available on Mykoweb: https://www.mykoweb.com/CAF/index.html

• "Dennis E. Desjardin". Wikipedia website. Provides a brief biography of Desjardin and references. See: https://en.wikipedia.org/wiki/Dennis_E._Desjardin

• Desjardin, Dennis E.; Wood, Michael G.; Stevens, Frederick A. California Mushrooms: The Comprehensive Identification Guide (Timber Press, 2015). See:  https://www.californiamushrooms.us/index.html

• Harry D. Thiers Herbarium (SFSU). Dr. Desjardin was curator at the SFSU Herbarium for many years. 

• "Mushroom Lights up the Night in Brazil", EurekAlert!, July 6, 2011. Desjardin and his team at SFSU reclassifies bioluminescent mushroom from Agaricus gardneri to Neonothopanus gardneri. At the time, they were researching bioluminescence in mushrooms. See: https://www.eurekalert.org/news-releases/738500

• Hemmes, Don E; Desjardin, Dennis E. Mushrooms of Hawai'i: An Identification Guide (Echo Point Books & Media, 2016).

• Sempera Organics website. This company grows and produces mushrooms and mushroom-related products in a farm lab. Dr. Desjardin joined Sempera as its Chief Mycologist upon retirement from SFSU in 2021. https://semperaorganics.com/team/

• "Spongiforma squarepantsii". Wikipedia website. A fungus specimen whimsically named by Desjardin in 1984. See: https://en.wikipedia.org/wiki/Spongiforma_squarepantsii