Cortinarius orellanus

Cortinarius orellanus

Cortinarius orellanus, commonly known as the Fool's Webcap

Cortinarius orellanus, commonly known as the Fool's Webcap, is a highly toxic species of fungus in the family Cortinariaceae. It is notorious for causing severe renal failure if ingested, due to the presence of the toxin orellanine.

Description

The fruiting body of Cortinarius orellanus is characterized by its reddish-brown cap, which can range from 3 to 8 cm in diameter. The cap is initially convex, becoming more flattened with age. The surface is dry and fibrous, often with a slight umbo.

The gills are adnate to adnexed, starting out pale and becoming rusty brown as the spores mature. The stipe is cylindrical, measuring 5 to 10 cm in height and 0.5 to 1.5 cm in thickness, with a bulbous base. It is often covered with a fine, whitish cortina when young.

Distribution and habitat

Cortinarius orellanus is found in Europe, particularly in deciduous forests. It forms mycorrhizal associations with broadleaf trees, especially oak and beech. The fruiting season is typically from late summer to autumn.

Toxicity

Close-up of the cap and gills of Cortinarius orellanus

The primary toxin in Cortinarius orellanus is orellanine, a bipyridine alkaloid that causes delayed nephrotoxicity. Symptoms of poisoning may not appear until 2 to 3 days after ingestion, and can include nausea, vomiting, abdominal pain, and polyuria. If untreated, it can lead to acute kidney injury and chronic kidney disease.

There is no specific antidote for orellanine poisoning, and treatment is primarily supportive, including hemodialysis in severe cases.

Related species

Cortinarius orellanus is part of a group of toxic species known as the Orellani. Other related species include Cortinarius rubellus and Cortinarius speciosissimus, which also contain orellanine.

Related pages

• Cortinarius
• Mycology
• Mushroom poisoning
• Nephrotoxicity