| Russula emetica | |
|---|---|
| Scientific classification | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Homobasidiomycetae |
| Subclass: | Hymenomycetes |
| Order: | Russulales |
| Family: | Russulaceae |
| Genus: | Russula |
| Species: | R. emetica |
| Binomial name | |
| Russula emetica (Schaeff.: Fr.) Pers. |
|
| Russula emetica | |
|---|---|
| Mycological characteristics | |
| gills on hymenium | |
| cap is convex | |
| hymenium is free | |
| stipe is bare | |
| spore print is white | |
| ecology is mycorrhizal | |
|
edibility: edible or poisonous |
|
Russula emetica, commonly known as the sickener, is a basidiomycete mushroom of the genus Russula, one of many species with a predominantly red-coloured cap and white gills and stalk. It gets its common name from its inedibility, as it causes vomiting and diarrhea when consumed. It has an extremely peppery taste, which is said partly to disappear on cooking, along with its toxicity, though eating it is not recommended. Mixing one emetica with otherwise edible red Russula will ruin the whole meal, and it is a common reason some do not pick any red Russula-species.
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R. emetica was first described as Agaricus emeticus by Jacob Christian Schaeffer in 1774,[1] before being placed in the new genus Russula by Christian Hendrik Persoon in 1796, where it remains. Its specific epithet is derived from the Ancient Greek emetikos/εμετικος 'emetic' or 'vomit-inducing'.[2] Similarly, its common names of sickener, emetic russula and vomiting russula also refer to this attribute.
The uncommon European subspecies R. emetica longipes is distinguished by its longer stalk and ochre-coloured gills.[3] The paler European mushroom Russula betularum of coniferous forests and moorland is sometimes considered a subspecies.[3]
The sticky cap is 3–10 cm (1¼–4 in) wide and a bright scarlet or cherry red in colour with finely ridged margins. The cuticle is readily peeled from the cap.[4] It is initially convex, then later flat, or depressed. The brittle flesh is white and the taste is very sharp and peppery. The spore print is white, as are the narrowly spaced gills. The stipe is up to 7 cm (3 in) long and 1 cm (½ in) wide, cylindrical and white.[5] The fungus has an unusual fruity smell.
It is one of many red-coloured species of Russula; the related Beechwood Sickener (R. nobilis) is found under beech in Europe. Many, such as the paler R. sanguinaria, are inedible, though R. aurea is edible and good: it has a yellow stem, gills and flesh under its red cap.[6] Another inedible species, R. fragilis has notched gills, and its stalk stains blue with naphthol.[7] The red pigments of this and other russulas are water soluble to some degree, and fruiting bodies will often bleach or fade with rain or sunlight.[8]
Spores are roughly spherical, with dimensions of 8–10 µm; they are hyaline, and covered with small spines (echinulate).[4]
The Sickener may be found in wet places in coniferous woodlands in Europe, North Africa, Asia and North America, and can be very common.[3] There is some doubt over the extent of its range in North America, as some sightings refer to the related Russula silvicola; initially the name "Russula emetica" was often applied to any red-capped white russula encountered. Sightings in Australia are now referred to the similarly coloured Russula persanguinea.
As its name implies, the Sickener is inedible, though not as dangerous as once described in older mushroom guides. The symptoms are mainly gastrointestinal in nature: diarrhoea, vomiting and colicky abdominal cramps. The active agent has not been identified but thought to be sesquiterpenes, which have been isolated from the related genus Lactarius and from Russula sardonia.[9]
The bitter taste does disappear on cooking and it is said to be edible, though not recommended.[7] A study in England and southern Scotland found that the Red Squirrel (Sciurus vulgaris) is known to forage for, store and eat the Sickener.[10]