THE DECEPTIVE BEAUTY OF Cortinarius: A Guide to these Potentially Deadly Mushrooms

 By: Saswati Pathak

Introduction: 

 A genus of mushrooms known as Cortinarius grows in magnificent arrays of purple, brown, yellow, and red deep within the Northern Hemisphere's damp forests. One of the biggest genera of mushrooms in the world, Cortinarius contains more than 2,000 species. Regardless of their striking appearance, many of these mushrooms have a deadly secret: some of them contain toxins that can damage kidneys permanently. 

What Are Cortinarius Mushrooms?  

The characteristic "cortina" or veil-like structure that extends from the stem to the cap edge in young specimens is what differentiates Cortinarius mushrooms, also referred to as webcaps or cortinas. This cortina often forms a web-like ring or remnants on the stem as the mushroom ages. 

Generally, these mushrooms have: 

• Rusty-brown spores 
• Convex to flat caps 
• A fibrous veil (cortina) connecting the cap to the stem 
• Various colors, though many species display vibrant purples, reds, or oranges

image: characteristic features of Cortinarius mushroom

image source: https://explore.beatymuseum.ubc.ca/mushroomsup/C_hinnuleus.html

The Deadly Ones: Spotlight on Toxic Species 

Some species of Cortinarius contain lethal toxins that have resulted in death and irreversible organ damage, but not all of them are poisonous. Among the most notorious are: 

Cortinarius orellanus (Deadly Webcap) 

image: Cortinarius orellanus

image source: https://www.inaturalist.org/taxa/337849-Cortinarius-orellanus

Orellanine, a lethal nephrotoxin that selectively targets and destroys kidney tissue, is found in C. orellanus, possibly the most dangerous member of the genus. This toxin's delayed reaction time makes it especially pernicious; symptoms might not show up for 3–14 days after ingestion, making diagnosis very challenging. 

Cortinarius rubellus (Deadly Galerina)

image: Cortinarius rubellus

image source: https://en.wikipedia.org/wiki/Cortinarius_rubellus

This species has high levels of orellanine, just like C. orellanus. It is especially dangerous because of its orange-brown color and coniferous forest habitat, which can lead to it being mistaken for an edible species. 

Cortinarius speciosissimus (Magnificent Webcap) 

image: Cortinarius speciosissimus

image source: https://www.alamy.com/stock-photo/cortinarius-speciosissimus.html?sortBy=relevant

It is another species that contains orellanine and has been linked to multiple poisoning cases in Europe. Inexperienced foragers find it appealing due to its vivid coloring. 

The Silent Killer: Orellanine's Mechanism of Action 

The mechanism and chronology of orellanine toxicity are what make Cortinarius poisoning so dangerous: 

1. Delayed Onset: Usually, symptoms don't show up for two to fourteen days following ingestion. 
2. Irreversible Damage: By destroying proximal tubule cells, the toxin results in irreversible kidney damage. 
3. No Antidote: Orellanine poisoning does not have a specific remedy. 
4. Progression: Kidney failure gradually develops from the flu-like symptoms at first. 

The kidneys have frequently already suffered severe damage by the time symptoms show up. In extreme situations, patients need kidney transplantation or dialysis for the rest of their lives. 

Cortinarius poisoning symptoms 

Look for these symptoms, which usually appear gradually, if you think you may have Cortinarius poisoning: 

Initial Symptoms (2–14 days after ingestion): 

• Nausea and vomiting 
• A headache 
• Pain in the muscles 
• Fatigue 
• Dry mouth and thirst 

Subsequent Symptoms: 

• Decreased or no urine output 
• kidney pain 
• swelling of the extremities 
• Kidney failure signs 

Identification Challenges 

The difficulty in accurately identifying Cortinarius mushrooms is what makes them especially dangerous: 

• There are thousands of species in the genus that share similar appearances. 
• Depending on age and growing conditions, colors can change significantly. 
• For a positive identification, many species need to be examined under a microscope or tested chemically. 
• Certain poisonous species look like edible mushrooms from different genera. 

 Many foraging guides just advise avoiding the entire genus because even knowledgeable mycologists occasionally have trouble identifying Cortinarius.

Historical Poisoning Cases 

Throughout history, Cortinarius poisonings have been reported, with a number of noteworthy cases: 

• When a Polish family ingested C. orellanus in 1957, all of them developed kidney failure. 
• Due to several poisoning incidents in Europe in the 1970s, people became more aware of these dangerous mushrooms. 
• A forager in the United States in 1996 caused irreversible kidney damage when they mistakenly identified C. rubellus as an edible species. 

Guidelines for Foragers: 

Take note of these important safety precautions if you want to forage mushrooms: 

1. Never eat a mushroom unless you are positive that it is what it is. 
2. Regardless of their stated edibility, steer clear of all Cortinarius species. 
3. Employ a variety of identification techniques, such as chemical testing, field guides, and spore prints. 
4. When in doubt, seek advice from knowledgeable mycologists. 
5. Keep in mind that no meal is worth dying or suffering irreversible kidney damage. 

Options for Treatment 

If Cortinarius poisoning is suspected: 

1. Get medical help right away. 
2. If possible, bring samples of mushrooms. 
3. Supportive care is usually the focus of treatment. 
4. Kidney failure may require hemodialysis. 
5. Kidney transplantation may be necessary in extreme circumstances. 

Conclusion 

The Cortinarius genus represents both the beauty and danger of the fungal world. Their vibrant colors and interesting growth patterns make them fascinating subjects for photography and study, but their potential toxicity demands extreme caution. 

For those interested in mushrooms, these species serve as an important reminder that nature's most attractive offerings sometimes hide deadly secrets. The best approach to Cortinarius is to admire them with your eyes only, leaving them undisturbed in their natural habitat where they play important ecological roles in forest ecosystems. 

Remember the old forager's adage: "When in doubt, throw it out." With Cortinarius, it's better to never pick them in the first place. 

 

Disclaimer: This blog is for informational purposes only. Never consume wild mushrooms without proper identification by an expert mycologist. Always seek immediate medical attention if mushroom poisoning is suspected.