Poisonous Mushrooms


A common pastime of outdoor enthusiasts is collecting edible mushrooms. This  must be pursued with great caution since mistaking a poisonous mushroom for one that is edible can cost you your life. There are many old wives tales that would have you believe that there are easy ways to avoid poisonous mushrooms.  However, the only way to avoid poisonous mushrooms is through 100% positive identification.

The toxins of mushrooms are put in four categories. The most serious of these categories is the toxins that act as cellular poisons. These include cyclopeptides and monomethylhydrazines, which rupture cell membranes in many internal organs such as the liver, kidneys, central nervous system and red blood cells. Mushrooms that contain these toxins include certain species in the genera Galerina, Amanita, Gyromitra, and Lepiota. The scary part of this type of poisoning is that the symptoms may not occur until 6 to 48 hours after ingestion, and such poisoning is severe to deadly.

The second group of toxins affects the nerves and is also quite serious. Species of Clitocybe, Inocybe, Psilocybe, Panaeolus, and Amanita can have these toxins, which include muscarine, ibotenic acid-muscimol, muscazone, aqnd psilocybine-psilocin. Symptoms of this poisoning can occur within a couple hours of ingestion and include abdominal pain, vomiting, diarrhea, and dehydration. Nerve poisoning can be fatal.

The third group of toxins causes gastrointestinal irritations. This category contains the majority of poisonous mushrooms and includes quite a variety of different toxins. Species of Agaricus, Boletus, Lactarius, Morchella, and Russula fall into this category, despite some of these genuses containing edible counterparts. Symptoms of this poisoning can occur within 2 hours of ingestion.

The fourth category contains mushrooms that are toxic when consumed with alcohol. Several species of Coprinus are edible except when ingested with alcohol.  Some morels and other mushrooms share these toxic properties. These particular toxins arrest the metabolism of the alcohol and causes vasomotor reactions, nausea, and vomiting.

Sometimes mushroom poisoning can occur through environmental factors. Mushrooms can act as sponges and absorb pesticides and pollutants in the environment, making a mushroom that is normally edible toxic. There are also allergies to mushrooms, and some individuals may be sensitive to certain edible varieties while others aren’t. Lastly, food poisoning can occur through improper handling and storage of mushrooms.


Here are a few ways to identify poisonous mushrooms:

1. Warts or scales on the cap. Note the off colored “patches” on the top of the picture to the left. These are the remnants of the universal veil that surrounds the mushroom when it is young. Sometimes these patches look more like rows of raised dots, as seen on the pictures further down.

2. A parasol or umbrella shaped cap. Each of these pictures is a good example of how an amanita cap is shaped, convex like a wide, upside down letter U. Or, for my fellow math enthusiasts, like an inverted parabola!



identify poisonous mushrooms3. The presence of a bulbous cup or sac around the base. This rounded cup is called the “volva” and is another remnant of the universal veil. It is often under the ground so you may have to gently dig up the mushroom to see it. The Amanita muscaria (commonly known as a “toadstool”) to the left is a great example of this bulbous base.

4. A white spore print. When an amanita cap is placed face down on a dark colored sheet of paper, it will often leave a spore print that is white.




identify amanita mushrooms5. The presence of a ring around the stem. This ring, called the “annulus”, is where the partial veil was attached to the stem before it tore apart as the mushroom grew. Check out the white mushroom to the left, you can see this ring quite clearly.

6. Gills that are thin and white. The underside of this example shows the white gills of an amanita. Just another thing to look for when trying to identify poisonous mushrooms.




Amanitas usually start appearing during the second half of the season, in summer and fall. Look for them in woodlands on the ground. In many places they are quite common.


Also just because I have too, please don’t try this at home seek a professional first. And always be safe!

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