# Cortinarius orellanus

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***Cortinarius orellanus***, commonly known as the **fool's webcap** or **fools webcap**, is a species of deadly fungus in the family [Cortinariaceae](/source/Cortinariaceae) native to Europe. Within the genus it belongs to a group known as the [Orellani](/source/Orellani), all of which are highly toxic—eating them results in [kidney failure](/source/Kidney_failure), which is often irreversible. The mushroom is generally tan to brown all over.

## Taxonomy

*Cortinarius orellanus* was first described by Swedish mycologist [Elias Magnus Fries](/source/Elias_Magnus_Fries) in his 1838 book *Epicrisis Systematis Mycologici seu Synopsis Hymenomycetum*.[1] It is one of seven highly toxic species that make up the [orellani](/source/Orellani), a subgenus within genus *Cortinarius*.[2]

## Description

*Cortinarius orellanus* has a concave [cap](/source/Pileus_(mycology)) of 3 to 6 centimetres (1.2 to 2.4 in) diameter, though rare specimens reach 8 centimetres (3.1 in) across. The cap flattens with age. In colour, it is an orange-brown, and is covered in fine, fibrous scales but become smooth with age. The cap surface turns black with potassium hydroxide. The thick [gills](/source/Lamella_(mycology)) are light ochre-coloured, changing to a rust-brown with age as the spores mature. They have an [adnate or sinuate](/source/Lamella_(mycology)#Classification) connection to the stipe. The [stipe](/source/Stipe_(mycology)) is 4 to 9 centimetres (1.6 to 3.5 in) tall, and 1 to 2 centimetres (0.39 to 0.79 in) thick with a tapering base. It is the same colour or slightly paler than the cap, and is yellowish at the top. There are occasionally fragments of the pale yellow veil (cortina) attached to its lower half. The firm [flesh](/source/Trama_(mycology)) is pale ochre. It smells slightly of radishes when cut and has no strong taste.[3]

## Distribution and habitat

*Cortinarius orellanus* occurs in central and eastern Europe (Poland, Czech Republic, Slovakia), though is rare in Germany. It is occasionally found in southern Britain. It grows in deciduous forests under beech, hornbeam and oak, often near pine trees.[3]

## Toxicity

The danger of *C. orellanus* was uncovered in 1957,[4] after (in 1952) 102 people fell ill after eating it in [Bydgoszcz](/source/Bydgoszcz), Poland. Eleven of the victims died.[3][4] Since then, cases of poisoning have been recorded in France, Switzerland, and Germany.[4] In 1997, four people suffered [renal toxicity](/source/Nephrotoxicity) after mistaking *C. orellanus* for the edible and prized [chanterelle](/source/Chanterelle) in Austria, where wild mushroom picking is popular.[5]

The relevant toxin is [orellanine](/source/Orellanine).[6]

One important feature of Cortinarius orellanus's natural history is its toxicity, which is linked to the presence of orellanine, a strong nephrotoxin. The research publications provide strong evidence for this claim, especially the one by Judge et al. (2010) that describes cases of chronic renal failure brought on by consumption of orellanine-containing Cortinarius mushrooms.

## See also

- [List of deadly fungus species](/source/List_of_deadly_fungus_species)

## References

Judge, B. S., Ammirati, J. F., Lincoff, G. H., Trestrail III, J. H., & Matheny, P. B. (2010). Ingestion of a newly described North American mushroom species from Michigan resulting in chronic renal failure: Cortinarius orellanosus. Clinical Toxicology, 48(6), 545-549.

1. Fries, E. M. (1838). [*Epicrisis Systematis Mycologici: Seu Synopsis Hymenomycetum*](https://web.archive.org/web/20201021105651/http://www.librifungorum.org/Image.asp?ItemID=634&ImageFileName=0288b.jpg) [A Critical Study of Mycology: A Synopsis of the Hymenomycetes] (in Latin). Vol. 1–2. Uppsala, Sweden: Regiae Academiae Typographia. p. 288. Archived from [the original](http://www.librifungorum.org/Image.asp?ItemID=634&ImageFileName=0288b.jpg) on October 21, 2020.

1. Gasparini, B. (2004). ["*Cortinarius* subgenus *Orellani* in Australia and in the world"](http://media.wix.com/ugd/86d4e0_8dc7de09f7b74fb28367b59a29975599.pdf). *Australasian Mycologist*. **23** (2): 62–76.

1. Bresinsky, A. & Besl, H. (2004). [*A Colour Atlas of Poisonous Fungi: A Handbook for Pharmacists, Doctors, and Biologists*](https://books.google.com/books?id=EIcQGsZ2kksC&pg=PA54). CRC Press x. pp. 53–54. ISBN 9780723415763.

1. Prast, H.; Werner, E. R.; Pfaller, W.; Moser, M. (1988). "Toxic properties of the mushroom Cortinarius orellanus". *Archives of Toxicology*. **62** (1): 81–88. [doi:10.1007/BF00316263](https://doi.org/10.1007/BF00316263). [PMID 3190463](https://pubmed.ncbi.nlm.nih.gov/3190463). [S2CID 24495871](https://api.semanticscholar.org/CorpusID:24495871)

1. Horn, S.; Horina, J. H.; Krejs, G. J.; Holzer, H.; Ratschek, M. (1997). "End-stage renal failure from mushroom poisoning with *Cortinarius orellanus*: Report of four cases and review of the literature". *American Journal of Kidney Diseases*. **30** (2): 282–86. [doi:10.1016/S0272-6386(97)90066-4](https://doi.org/10.1016/S0272-6386(97)90066-4). [PMID 9261043](https://pubmed.ncbi.nlm.nih.gov/9261043)

1. Richard, Jean-Michel; Louis, Josette; Cantin, Danielle (1 March 1988). "Nephrotoxicity of orellanine, a toxin from the mushroom *Cortinarius orellanus*". *Archives of Toxicology*. **62** (2–3): 242–245. [Bibcode:1988ArTox..62..242R](https://ui.adsabs.harvard.edu/abs/1988ArTox..62..242R). [doi:10.1007/BF00570151](https://doi.org/10.1007/BF00570151). [ISSN 0340-5761](https://www.worldcat.org/issn/0340-5761). [PMID 3196164](https://pubmed.ncbi.nlm.nih.gov/3196164). [S2CID 36515278](https://api.semanticscholar.org/CorpusID:36515278)

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