''Cortinarius orellanus'', commonly known as the fool's webcap or fools webcap, is a species of deadly fungus in the family Cortinariaceae native to Europe. Within the genus it belongs to a group known as the

Orellani The Orellani are a group of seven related species in the genus ''Cortinarius'' that have been classified as a section of the subgenus ''Leprocybe'' or a subgenus in their own right. They are among world's most poisonous mushrooms as they contain ...

, all of which are highly toxic—eating them results in

kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

, 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 Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. Career Fries was born at Femsjö (Hylte Municipality), Småland, the son of the pastor there. He attended school in Växjö. He acquired ...

in his 1838 book ''Epicrisis Systematis Mycologici seu Synopsis Hymenomycetum''. It is one of seven highly toxic species that make up the

orellani The Orellani are a group of seven related species in the genus ''Cortinarius'' that have been classified as a section of the subgenus ''Leprocybe'' or a subgenus in their own right. They are among world's most poisonous mushrooms as they contain ...

, a subgenus within genus ''Cortinarius''.

Description

''Cortinarius orellanus'' has a concave cap of diameter, though rare specimens reach 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 are light ochre-coloured, changing to a rust-brown with age as the spores mature. They have an adnate or sinuate connection to the stipe. The stipe is tall, and 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 is pale ochre. It smells slightly of radishes when cut and has no strong taste.

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.

Toxicity

The danger of ''C. orellanus'' was uncovered in 1957, after (in 1952) 102 people fell ill after eating it in

Bydgoszcz Bydgoszcz ( , , ; german: Bromberg) is a city in northern Poland, straddling the meeting of the River Vistula with its left-bank tributary, the Brda. With a city population of 339,053 as of December 2021 and an urban agglomeration with more ...

, Poland. Eleven of the victims died. Since then, cases of poisoning have been recorded in France, Switzerland, and Germany. In 1997, four people suffered renal toxicity after mistaking ''C. orellanus'' for the edible and prized chanterelle in Austria, where wild mushroom picking is popular. The relevant toxin is

orellanine Orellanine or orellanin is a mycotoxin found in a group of mushrooms known as the Orellani of the family Cortinariaceae. Structurally, it is a bipyridine N-oxide compound somewhat related to the herbicide diquat. History Orellanine first came t ...

References

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