Russula emetica — Sickener or emetic russula

The sickener, Russula emetica

The sickener2, photograph by SeaRa Lim.

The sickener, Russula emetica

Pale yellow-capped variant of the sickener10, photograph by Benjamin Woo, with permission from the University of Washington, Burke Museum.

The sickener, Russula emetica

The delicate gills and flesh of the sickener11 crumble readily, as photographed here by Benjamin Woo, reproduced with permission from the University of Washington, Burke Museum.

The sickener, Russula emetica spores

The sickener12, sketch of basidiospore, notes by Benjamin Woo, with permission from the University of Washington, Burke Museum.

Fragile mushrooms, breaking easily into bits and pieces, with white gills and a fiery hot taste.


Odour: None, to generic mushroom-like.
Taste: Gills and flesh very hot/spicy. To test, chew on a pea-sized piece and then spit it out.
Cap: 4–10 cm in diameter, starting out convex. With age the cap flattens out, and has a depression in the centre. The margin is grooved up to 1 cm from the edge. The colour varies from red to pink with yellow blots and a red spot in the centre, to cream-coloured or white. The surface is viscid when wet. One can peel the cap cuticle off from the cap margin more or less halfway to the centre.
Gills: Adnate, white, crowded, with few if any shorter gills between the long ones.
Stem: 4–10 cm long x 0.5–1 cm wide, equally wide over the whole length or slightly widening towards the base. White, not discolouring when scratched. Sometimes brown at base with age. Stuffed, not hollow.
Ring or veil: None.
Cup: None.
Spores: 8–11 x 7–9 µm, with spines or warts ~1 µm tall that are connected by a low network of ridges.
Habitat: On the ground or on well-rotted wood in various types of coniferous forests, common; ectomycorrhizal. DNA barcoding studies indicated that R. emetica of the Pacific northwest were infrequent in bogs7. This conflicted with earlier interpretations of the species habitat8.
Geographic distribution: North America, forests of BC and the Pacific northwest into Alaska; Europe; possibly circumboreal.

Russulas are easy to recognize to genus by their brittle flesh and their white- to cream-coloured gills. Unlike the related genus Lactarius, they do not ooze milky or coloured juice (latex) where cut or broken. However, russulas are notoriously difficult to identify to species.

In the Pacific northwest, the sickener is perhaps the most common among a group of five closely related, similar Russula species. The odds are good that a Russula from BC or the Pacific northwest with a red, yellow or white cap, with white spores and with a fiery hot taste7 will be the sickener, although DNA sequence analysis would be needed to confirm the identification. None of these five species in the group are safe to eat and although parboiling and pickling may render them edible, at some point one has to ask "why bother?"

Toxins: Possibly sesquiterpenoids9.

Symptoms: vomiting, nausea, diarrhoea, and colicky stomach cramps, starting half an hour to three hours after consumption8. Patients have recovered as soon as the mushrooms have left the body.

Treatment: Contact your regional Poison Control Centre if you or someone you know is ill after eating wild mushrooms. Poison Centres provide free, expert medical advice 24 hours a day, seven days a week. If possible, save the mushrooms or some of the leftover food containing the mushrooms to help confirm identification.

Poison Control:
British Columbia: 604-682-5050 or 1-800-567-8911.
United States (WA, OR, ID): 1-800-222-1222.

1
MyCoPortal. Mycology Collections Portal, <http://mycoportal.org/portal/collections/harvestparams.php> accessed February 2018.

2
Specimen Russula emetica UBC F16571, GenBank #FJ627036.

3
Shaffer, R. L. Some common North American species of Russula subsect. Emeticinae. Beihefte zur Nova Hedwigia 51, 207-237 (1975).

4
Volk, T. Tom Volk's Fungus of the Month for September 2004, <http://botit.botany.wisc.edu/toms_fungi/sep2004.html> accessed January 2018.

5
Romagnesi, H. Les Russules d’Europe et d’Afrique du Nord. Essai sur la valeur taxonomique spécifique des characters morphologiques et microchimiques des spores et des revêtements. Bordas, Paris (1967).

6
Bazzicalupo, A. & Carmean, D. Ben Woo's Russula Mushrooms, <http://advance.science.sfu.ca/fungi/index.php?-link=Home> accessed March 2018.

7
Bazzicalupo, A. L. et al. Troubles with mycorrhizal mushroom identification where morphological differentiation lags behind barcode sequence divergence. Taxon 66, 791-810, doi:10.12705/664.1 (2017).


8
Edwards, J. N. & Henry, J. A. Medical problems of mushroom ingestion. Mycologist 3, 13-15, doi:https://doi.org/10.1016/S0269-915X(89)80006-0 (1989).


9
Kobata, K., Kano, S. & Shibata, H. New lactarane sesquiterpenoid from the fungus Russula emetica. Bioscience Biotechnology and Biochemistry 59, 316-318, doi:10.1271/bbb.59.316 (1995).


10
Specimen Russula emetica WTU-F-039500, GenBank #KX813542.


11
Specimen Russula emetica WTU-F-039015_f, GenBank #KX813585.


12
Specimen Russula emetica WTU-F-039500_b, GenBank #KX813542.