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The Genus Hypomyces  

[ Ascomycetes > Hypocreales > Hypocreaceae > . . . ]

by Michael Kuo

The species in Hypomyces are fungi that parasitize mushrooms, covering them with powders, pimply crusts, and so on. Often the parasite fungus so transforms the host mushroom that it's impossible to tell what the host was. The Lobster Mushroom, for example, is a Russula or Lactarius mushroom that has been covered with a bright orange Hypomyces species, Hypomyces lactifluorum.

Six of the most commonly collected Hypomyces species in North America are keyed out below. However, the authoritative online treatment of Hypomyces, for readers whose interest goes beyond figuring out what species of funky stuff is covering this or that mushroom, is the USDA's Hypomyces Web Site. I highly recommend the site; it contains extensive information on the genus. Sadly, however, the site is a nightmare to navigate. It "looks good," but it uses frames, coupled with more Javascript than ought to be legal. I would love to offer direct links to species pages at the site, but it isn't possible; you will need to navigate the Javascript yourself to get to the wonderful content.


Hypomyces hyalinus

Hypomyces completus

Key to 6 Commonly Collected Species of Hypomyces in North America  

1.Victim a species of Helvella; Hypomyces whitish to pinkish.

1.Victim a bolete or a gilled mushroom.

2.Victim a bolete.

2.Victim a gilled mushroom.

3.Hypomyces white throughout development; victim potentially any bolete but most commonly Suillus pictus.

3.Hypomyces white at first, becoming yellow as it matures; victim potentially any bolete.

4.Victim a species of Amanita, especially Amanita rubescens.

4.Victim a species of Russula or Lactarius.

5.Hypomyces greenish yellow, often confined to the stem and gills of the victim.

5.Hypomyces bright orange, usually completely engulfing the victim by maturity.


Harrison, K. A. & Grund, D. W. (1977). Nova Scotian fleshy fungi: A new albino variant of Hypomyces lactifluorum (Schw. Ex Fr.) Tulasne. Proceedings of the Nova Scotian Institute of Science 28: 87–91.

Poldmaa, K. (2003). Three species of Hypomyces growing on basidiomata of Stereaceae. Mycologia 95: 921–933.

Poldmaa, K., Farr, D.F., & McCray, E.B. (2006). Hypomyces online. Retrieved from the Systematic Botany & Mycology Laboratory, ARS, USDA Web site:

Rogerson, C. T. & Simms, H. R. (1971). A new species of Hypomyces on Helvella. Mycologia 63: 416–421.

Rogerson, C. T. & Samuels, G. J. (1994). Agaricolous species of Hypomyces. Mycologia 86: 839–866.

This website contains no information about the edibility or toxicity of mushrooms.

Cite this page as:

Kuo, M. (2006, October). The genus Hypomyces. Retrieved from the MushroomExpert.Com Web site:

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