It goes without saying that this month's fungus, Russula emetica, is not edible. That's the value of Latin names-- they convey something interesting about the fungus that helps you to remember it. In this case, emetica refers to the gastrointestinal "unpleasantness" induced by eating this mushroom. In other words, if you eat it, you will almost certainly throw up, undergo emesis, puke, ralph, buick, upchuck, hurl, heave, spew, have a TechnicolorTM yawn, toss your cookies, worship the porcelain goddess, or maybe even vomit!
Russula emetica is characterized by having a red cap (pileus) in which the cuticle peels 1/3-3/4 of cap radius, a pure white stem (stipe), and a very acrid or peppery hot taste. To test the taste of a mushroom, break off a very small piece of the cap and gills, about 2 mm X 2 mm, and chew it in your mouth, rolling it around all parts of your tongue for a few seconds, then SPIT IT OUT (i.e. do not swallow it). You should NEVER taste mushrooms you know to be deadly poisonous, such as Amanita bisporigera and the other death angels or Galerina autumnalis and related species. You probably should not taste possible hallucinogens such as Amanita muscaria or Psilocybe species, or even known gastrointestinal upsetters such as Omphalotus illudens or Chlorophyllum molybdites. Although it is unlikely that using this method you could absorb enough of any toxin to cause you any problems, I DO NOT TAKE RESPONSINBILITY FOR ANY OF YOUR ACTIONS. (How's that for a disclaimer?) In any case R. emetica is one of the hottest, most acrid members of its genus and among the hottest of mushrooms. As you can imagine, you will not have a pleasant dining experience for many reasons.
However, all that being said, there is some doubt as to whether we have true Russula emetica in North America, but indications are that we probably do. However, the species is probably restricted to Sphagnum bogs. In Europe, from where it was described by Fries, it certainly does exist. More news will be forthcoming as more DNA phylogenetic studies are done on the Russulales.
It is relatively east to identify a mushroom as a member of the genus Russula, although the species are quite difficult to distinguish. Russula and Lactarius species are unique among mushrooms in that they contain sphaerocysts, a fancy name for spherical cells that in profile appear round. These sphaerocysts cause the members of these genera to be more fragile than "regular" mushrooms of the same size and stature. In general, Russula species are even more fragile than Lactarius, such as Lactarius indigo, which also differs in having a milky latex exude from the gills when cut. In addition, the stem of both genera typically breaks very cleanly like a piece of chalk. Russula can be easily identified by the "drop-kick" method-- the mushroom should shatter into a million pieces if properly kicked. There are, of course, many exceptions to the drop-kick rule (such as the tough Russula brevipes and the very dense Russula compacta group), but it's fun to try anyway, especially in frustration in trying to identify most Russula species. In the pink picture "A" contains sphaerocysts of a Russula. Compare this with "B," the hyphal construction of a "regular" mushroom, in this case, an, Inocybe. It is not known why these sphaerocysts exist, but, along with amyloid ornamented basidiospores, they do place Russula and Lactarius in a different family called the Russulaceae. As it turns out, the Russulaceae have more in common with the polypore genera Bondarzewia, Albatrellus and Heterobasidion, the false truffles Zelleromyces and Macowanites, some tooth fungi, such as Hericium and Auriscalpium, the coral fungus Clavicorona pyxidata and even some of the corticioid (crust) fungi such as Gloeocystidiellum and Vararia. All of these have amyloid spores (blue in Melzer's reagent, which is mostly iodine), and along with the Russulaceae, they are placed in an order called the Russulales. You may recall that most of the other gilled fungi are in the Agaricales. One exception is Lentinellus, which gets classified in the Russulales. You can read more about the DNA studies that came to these conclusions at Steve Miller's Russulales Website at the University of Wyoming. In particular see his Phylogenetic tree of the Russulales.
All Russula and Lactarius species are mycorrhizal, which means they have a mutualistic association with the roots of trees, especially members of the oak family (Fagaceae) and pine family (Pinaceae). In this mutualism, the fungus receives sugars from the tree's photosynthesis, while the trees benefit by the fungal ability to absorb water and minerals, particularly phosphorous and nitrogen. Thus both organisms benefit, and neither one would survive very well without the other. Plants with mycorrhizae have a definite competitive advantage of those without. In fact, more than 90% of vascular plants form some sort of mycorrhizal association.
Although most of the species prefer wet weather, it's a common occurrence that Russulas can be found when it's very dry, and there aren't many other mushrooms around. Sometimes Russulas can compose the greatest amount of mushroom biomass collected on your foray into the forest on any particular day. Besides benefiting the trees, thee is a large input of energy to the forest ecosystem benefits by this large amount of biomass. In particular, Russula species make great food for slugs, as shown to the left and below to the right. As long as it's wet, the slugs will be out eating what seems to be quite a treat for them.
There are hundreds, if not thousands of Russula species, most of which are not well characterized nor well delimited, mostly because they are obligate mutualists and cannot be cultured. Most species are very difficult to identify. Even if you find a red Russula and think it's R. emetica, you're probably wrong. At Bart Buyck's Russulales News you can find an online key to the Russula species in North America by Geoff Kibby and Ray Fatto. 
According to their key, I counted 128 (one hundred twenty-eight!!) species of Russula that can have a red pileus-- 83 of these have a red pileus and an entirely white stem! Some characters that must be noted are:
- Color and size of the cap (pileus)
- Color of the stem, including any changes in color between the bottom of the stem and the top
- Exact color of the gills
- Exact color of the spore print (ranges from pure white to cream to tan to almost yellow)
- Whether or not the cap cuticle peels, and to what extent
- Taste (acrid, mild, or bitter)
- Any staining reactions of the stem or the cap on bruising (usually some gray or brown)
- Whether or not the gils fork dichotomously (rare)
- Odor (some smell vaguely of fish or shrimp, and others smell like almonds or maraschino cherries--some just smell indescribably foul)
- Basidiospore length and ornamentation, as well as many other microscopic features.
For more pictures of the Russulales see my pictures of the Russulales. I have lots more on my computer.
For LOTS more great information and more pictures of the Russulales see these two great sites. Both are excellent resources.
I hope you enjoyed learning something about Russula emetica and the rest of the Russulales. They are beautiful and photogenic mushrooms, but frustrating and difficult to identify to species. However, with some practice, you can do it! Good Luck! Otherwise just enjoy their beauty.
If you have anything to add, or if you have corrections, comments, or recommendations for future FotM's (or maybe you'd like to be co-author of a FotM?), please write to me at volk.thom@uwlax.edu
This page and other pages are © Copyright 2004 by Thomas J.
Volk, University of Wisconsin-La Crosse.
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