Below you'll find a list of common characteristics to help you identify poisonous mushrooms of the Amanita genus. This list is by no means the final word! Weather and other environmental factors can change the shape of a mushroom, making it difficult to identify.
So please remember that this is just a guide to supplement learning, which should be done through books and especially guided forays. Don't eat any mushroom based on what you've read here!
An Amanita forms as a small button in the shape of an egg. The outside of the "egg" is actually a layer of tissue surrounding the mushroom known as the "universal veil". Often it will have a "partial veil" as well, which is a layer of tissue that covers just the gills before the mushroom is old enough to produce spores. Eventually these veils break as the mushroom grows.
During the young button phase it's easy to mistake an Amanita for a puffball. This is why it's so important to slice open a puffball mushroom and check to make sure it's solid inside. Finding gills indicates that it's not a puffball at all, but possibly a deadly Amanita.
While not all amanitas are deadly, some contain the powerful toxin amanitin. Amanitin is thought to be the most lethal of all mushroom toxins and is found in both the death cap and the destroying angel. For an interesting article on how poisonous mushrooms produce amanitin see this article from Science News.
Below are common traits that will help you identify these poisonous mushrooms (with some visual aids, of course!).
1. Warts or scales on the cap. Note the off colored "patches" on the top of the picture to the right. 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!
3. 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.
5. 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 right, 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.
Knowing how to identify poisonous mushrooms will go a long way towards the prevention of poisoning yourself. Although there are some deadly species (and many more that will just make you sick), with the right knowledge and common sense mushroom hunting isn't as dangerous as some would believe. Remember to never eat anything that you haven't positively identified at least three times. Also never do this:
Not to be tried at home! ;)