Learn the Deadly Mushrooms

For his final exam, it is said that a prominent American mycology professor used to ask each student to select one of several mushrooms arranged on a table, and take a bite. Among the mushrooms, the story goes, were some deadly poisonous species. I suspect this is an urban legend, but I'm not sure. At any rate, it's a test you will be taking if you begin collecting wild mushrooms for the table.

Sadly, people die every year in the pursuit of edible wild mushrooms. Many, many species of mushrooms are poisonous and can hospitalize a healthy adult or kill a small child or frail adult. A few species will kill anyone. Obviously, anyone who's even thinking about gathering wild mushrooms in order to eat them should take the time to learn how to recognize the deadly poisonous mushrooms!

Don't Eat Amanitas

The Amanitas may be among the most beautiful of all mushrooms--but they can be fatal for those who eat them. The Death Cap (top illustration) and the Destroying Angel (second illustration), as well as several other Amanitas, contain amatoxins, which are horrific and deadly poisons (see The Deadliest Toxins for more information).

The whole genus Amanita is to be avoided, regardless of what you may read in (irresponsible) field guides. I have seen "edible" and poisonous Amanitas growing together, imitating each other, and extremely difficult to distinguish. Avoid (eating) any mushroom with a basal bulb and/or a volva (a sac-like covering; see the top illustration), and any mushroom that has wart-like patches--or a single patch--of material on its cap.

Several other species of Amanita contain other poisons, including ibotenic acid and muscimol (Amanita muscaria, Amanita pantherina, Amanita gemmata, and others). These poisons are not always lethal, but they can easily lead to hospitalization.

See the pages on Amanitas for more information.

Don't Eat Little Brown Mushrooms

The mushrooms in the third and fourth illustrations also contain amatoxins, as do some of their close relatives. They are every bit as deadly as the lethal Amanitas.

LBMs ("Little Brown Mushrooms") are very hard to identify, and there are thousands of them. Many of them require a microscope if you want to be sure of identification. Best to leave them alone if you are picking mushrooms for the table!

Galerina marginata (also known as "Galerina autumnalis"), the third illustration, is a small, orange-brown mushroom found growing on logs and sometimes in moss. It can be found in the spring, summer, and fall.

Conocybe filaris, the fourth illustration, is another deadly LBM. It is terrestrial, and comes up in fall and winter.

Other Killers and Potential Killers

Several species of Lepiota contain amatoxins; all of the Lepiotas should be avoided, including the Parasol Mushroom, Macrolepiota procera, until you have years of mushrooming experience under your belt and are very sure of your identification.

The false morels can be fatally poisonous, though it is rare. The poison in false morels is MMH, or monmethylhydrazine (a chemical also found in rocket fuel). Though MMH is not understood completely by scientists, there is no question about whether it is poisonous or not. It appears that MMH may occur in different quantities in different false morels (even members of the same species), that its presence may vary according to geography, that its affect on people may vary between individuals, and that its toxicity may be cumulative (raising the possibility of eating false morels safely for years and then, one day, croaking after one bite). Clearly, MMH is not to be messed with. See the pages on Gyromitras for more information--also the page on False Morel Toxicity.

One frequent cause of mushroom poisoning involves people who move from one part of the world to another, then search for the mushrooms they've always eaten. What they find may look like the mushroom they're used to, but it may not be the same thing! This kind of tragic poisoning sometimes occurs when people move from an area where wild mushrooms are more commonly eaten--like Korea, or Eastern Europe--to the United States and Canada.

Back 01.01.2008