Russula emetica

What You Should Know

Very common and widespread in coniferous woodlands throughout Britain, Ireland, and mainland Europe as well as in northern Africa and some Asian countries. The Sickener also occurs in many parts of North America.

Other names: The Sickener, Emetic Russula, Vomiting Russula.

Russula emetica and Edible Species

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. Though in other European countries some are collected regularly for eating.

The Geranium Scented Russula is listed as poisonous by some sources and The Sickeners or Emetic Russulas do as the name suggests. Though one family member (Russula subnigricans) found in China, Japan, and reportedly even the US, has been listed as deadly.

By sight it can be extremely hard, if not impossible to tell exactly what Russula you have found without the aid of a microscope.

Before you can test a Russula to see if it’s edible you have to be 100% sure you have a Russula!

Russula emetica Identification

1. Cap

   Scarlet, fading in wet weather (the pigment in the cap cuticle is somewhat water-soluble); peeling almost to center; the flesh of Russula emetica is pink beneath the cuticle; cap surface smooth, convex, sometimes becoming slightly depressed when fully mature; margin knobbly with small, rounded bumps irregularly spaced) and slightly striate; 3 to 10cm across.

2. Gills

   White, turning pale cream; adnexed or free; crowded.

3. Stem

   White, sometimes yellowing slightly with age; cylindrical, the base slightly clavate; 4 to 9cm long, 0.7 to 2cm in diameter.

4. Spores

   Ellipsoidal, 8-11 x 7.5-8.5µm, with conical warts to 1.2µm tall linked by narrow connectives to form a well-developed reticulum. The spore print is white or very pale cream.

Russula emetica Look-Alikes

There are many, many russulas and many red russulas. It is often difficult to tell one from another. You can identify mushrooms in the genus Russula by their blocky shape and their brittleness. They will break apart in your hand like a piece of chalk. The stalk even looks like a piece of chalk.

Another of the ‘red for danger’ brittlegills, this mushroom is very similar in appearance to the Beechwood Sickener, Russula nobilis.

Differentiating features are the greater brittleness of Russula nobilis is just as poisonous as Russula emetica and so both should be avoided when gathering mushrooms for food.

Several other red-capped brittlegills can only be separated from Russula emetica by thoroughly following one of the specialist keys, and in many cases, microscopic characters such as spore ornamentation have to be studied using an oil-immersion lens.

Russula emetica Taxonomy and Etymology

First described in 1774 by German mycologist Jacob Christian Schaeffer, who named it Agaricus emeticus (most gilled fungi were placed in the Agaricus genus in the early days of fungal taxonomy), this mushroom was later transferred to the genus Russula by Christian Hendrik Persoon in 1796.

Synonyms of Russula emetica include Agaricus emeticus Schaeff., Russula emetica var. emetica (Schaeff.) Pers., and Russula emetica var. gregaria Kauffman.

Russula emetica is the type species of the Russula genus.

Russula, the generic name, means red or reddish, and indeed many of the brittlegills have red caps (but many more are not, and several of those that are usually red can also occur in a range of other colors!). The specific epithet emetica surely needs no explanation.

Sources:

Photo 1 - Author: James Lindsey (Creative Commons Attribution-Share Alike 2.5 Generic)

Photo 2 - Author: Bob (Bobzimmer) (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 3 - Author: peupleloup (Creative Commons Attribution-Share Alike 2.0 Generic)

Photo 4 - Author: James Lindsey (Creative Commons Attribution-Share Alike 2.5 Generic)