Tom Volk's Fungus of the Month for August 2001

This month's fungus is Hypomyces lactifluorum, the lobster mushroom

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lobster mushroms with lobster at Eagle Hill, Maine This month's fungus is Hypomyces lactifluorum, the lobster mushroom. Technically Hypomyces is a parasite of other mushrooms, turning them into lobster mushrooms. The whole thing is called the lobster mushroom because of its red "shell" on the outside with white inside, much like cutting open a lobster, as shown to the left in my delicious dinner last August at the Humboldt Field Research Institute, Eagle Hill, Maine, where I taught a class on basidiomycetes. However, the red crust on the outside is the stromatic sterile tissue of the ascomycete (Hypomyces), and the white flesh on the inside is the flesh of a basidiomycete mushroom, presumably a Russula or Lactarius (more on this later). It's almost like mycological cannibalism! Not so coincidentally the title of my lecture at the Northeast Mycological Federation Foray at U-Mass in August is/was "Mycological Cannibalism: Fungi that eat other fungi." I'll tell you about some of the others briefly here.

lobster mushroom longitudinal section.  Doesn't it look like lobster?There are a number of other fungi that get their nutrition directly from other fungi, parasitizing them. Most of the spectacular ones parasitize the fruiting body of the host, but there are likely many more (like Trichoderma) that just parasitize the vegetative mycelium. Some examples are Tremella species on Stereum or other corticioid fungi, Asterophora parasitica on blackening Russula species, Psathyrella epimyces on Coprinus comatus, Spinellus on Mycena haematopus, Squamanita species on a wide variety of basidiomycete fungal hosts, and many dozens of examples of various Hypomyces species on a wide variety of hosts. One other important fungal parasite is one I'm about to publish a paper on with Dan Czederpiltz and Hal Burdsall, showing that Entoloma abortivum is actually the parasite in the relationship with Armillaria species, causing the Armillaria fruiting body to abort. We will recommend that the common name be changed to the abortive Entoloma, and the misshapen carpophoroids be called aborted Armillaria's. After the paper is published, I'll make Entoloma abortivum a FOTM and tell you the whole story.

Hypomyces and the Russula it's likely parasitizingSo I know you're going to ask "Is it edible?" well that's a complicated question. The Hypomyces part is known to be edible, but what about the host? Could the Hypomyces parasitize a poisonous mushroom? Apparently Hypomyces is a pretty good taxonomist, only parasitizing Russula or Lactarius species. According to Clark Rogerson and Gary Samuels, "In large populations of Hypomyces lactifluorum where the host can be determined with some confidence, the host has proven to be Russula brevipes; but associated nonparasitized hosts often belong to the Lactarius piperatus complex." Russula brevipes is a known edible, so it's not too surprising that the complex of these two species is edible. However Lactarius piperatus has an exceedingly hot flavor that renders it inedible for most people-- but that hotness is neutralized by the parasite Hypomyces, making it very delicious. It is conceivable that Hypomyces lactifluorum could parasitize a poisonous mushroom and cause problems for the mushroom eater. However, the lobster mushroom has been eaten for hundred of years without any known problems. If you eat this mushroom you're taking a very, very slim chance of there being a problem, in my opinion.

Some interesting ways to cook this mushroom are in a seafood stew or in a stir fry. It certainly adds an interesting red color and a crunchy texture to whatever you cook. You can even use it as Lobster HelperTM in lobster chowder!!.

There are many other species of Hypomyces. As the name would suggest, these grow on (literally *under*) mushrooms. Many of these are parasites of Agaricales, but a number of them grow on Aphyllophorales, especially polypores. see this page for a description and a key to other Hypomyces species and this page by Elwin Stewart and Gary Samuels for all you ever wanted to know about the Hypocreales.

Hypomyces cross section showing perithecia embedded in the orange stroma If you find one of these interesting mushrooms, I recommend you examine it more carefully. Cut a section of the mushroom as shown in the picture to the left. The small white flask-shaped pockets you see are the perithecia, where the cylindrical asci are borne. The orange part is the stroma, in which the perithecia are embedded. If you look at a section like this in the microscope, as shown to the right, Hypomyces lactifluorum perithecia you can see the perithecia, each with an opening (ostiole) to the outside of the fruiting body, through which the spores are ejected. In this particular section it is difficult to see the asci and the ascospores clearly, but they line the bottom of the perithecia. Incidentally, this microscopic picture was taken with my digital camera (Nikon CoolPix 950) through the eyepiece of a normal microscope, without any attachments and without removing the eyepiece. It's so easy. Make sure the automatic flash is turned off. It's a very cool technique tip I got at a conference a couple years ago. Try it yourself!

If you want to know more about the genus Hypomyces, I recommend you visit a site set up by the Systematic Botany and Mycology Laboratory, Beltsville MD and the Dept. of Plant Pathology at Penn State University on Hypomyces, featuring an interactive key, images, descriptions, distributions, and nomenclature. I think it's what every group of fungi needs!

I hope you enjoyed learning something about the lobster mushroom today. Things are not always as they appear-- here we have an ascomycete fungus parasitizing a basidiomycete mushroom, rendering it sterile. Hypomyces does not wipe out the population, however. It leaves some of the fruiting bodies alone, so that their host species can continue to proliferate and give the food in the future. Could we call this sustainable agriculture?

If you have anything to add, or if you have corrections or comments, please write to me at

This page and other pages are © Copyright 2001 by Thomas J. Volk, University of Wisconsin-La Crosse.

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