Hypomyces lactifluorum

Hypomyces lactifluorum (Schweinitz) Tulasne and C. Tulasne

Ecology and Morphology: Hypomyces lactifluorum is a mycoparasite on select Lactarius and Russula species growing amidst both conifers and hardwoods and can most often be found in the summer and fall months. This fungus will completely cover its host with orange perithecia, giving it a rough, warty appearance and texture. The parasitized mushroom fruiting body, when thoroughly engulfed by this mycoparasite will be firm, fairly hard, and somewhat brittle. Spore deposits from the parasite are white, while the ascospores themselves are hyaline when viewed under a compound microscope. Ascospores are spindle-shaped and measure roughly 35 x 43 x 6-7.5 µm.


Kingdom:        Fungi

Division:         Ascomycota

Class:             Sordariomycetes

Order:             Hypocreales

Family:            Hypocreaceae

Genus:             Hypomyces

Species:           H. lactifluorum


Figure 1. Hypomyces lactifluorum (PLP847_2018_200). H. lactifluorum parasitizing a large Lactarius spp. fruiting body growing in leaf litter on the floor of a hardwood forest. (left). The underside of the mushroom, showing even more of the warty texture of this mycoparasite (right).

Figure 2. Hypomyces lactifluorum (PLP847_2018_200). The warty texture and color of the orange perithecia covering the surface of the parasitized mushroom (A). The white spore deposit produced from H. lactifluorum (B). A broken perithecium (orange portion) with exposed asci (C). Spindle shaped ascospores contained within the long, slender asci (D).

Figure 3. The hardwood forest environment in which this mushroom was found and which is a typical habitat for H. lactifluorum.



Kuo, M., & Methven, A. S. (2014). Mushrooms of the Midwest. University of Illinois Press.

Kuo, M. (2003, January). Hypomyces lactifluorum: The lobster mushroom. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/hypomyces_lactifluorum.html

Volk, T. (2001). Tom Volk’s Fungus of the Month for August 2001. University of Wisconsin La-Crosse. Retrieved from Tom Volk’s fungus of the month: https://botit.botany.wisc.edu/toms_fungi/aug2001.html

Wood, M., & Stevens, F. (2017). California Fungi—Hypomyces lactifluorum. The Fungi of California. Retrieved from Mycoweb.co: http://www.mykoweb.com/CAF/species/Hypomyces_lactifluorum.html




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