How to Identify Poisonous Mushrooms. Wild mushrooms can be delicious--or they can be deadly. It can be difficult to tell the difference between the two because there are no specific rules to identify a poisonous mushroom. However, following a few steps can help you avoid ingesting the wrong fungi.
Contact your local poison control center for information on poisonous species in your area.
Memorize the features of the local poisonous mushrooms, especially Amanita, which has an umbrella-like cap, white gills, rings on the stem and a cup-like rounded base which is often under the soil. This is the most common poisonous mushroom.
Follow guidelines from a quality reference book such as "The Mushroom Hunters Field Guide" by Alexander H. Smith and Nancy Smith Weber or "The Audubon Society Field Guide to North American Mushrooms" by Gary H. Lincoff. Take all collected species home and identify them carefully against these references before ingesting.
Use systematic mycology to identify different mushroom species. In other words, follow a step-by-step check list of identifying characteristics. Many poisonous species will be eliminated if you never collect little brown mushrooms, umbrella-capped mushrooms with white gills or mushrooms that are showing signs of age or decay.
Always taste a small amount of the fleshy cap from a mushroom you think is not poisonous before consuming the whole thing. Wait 24 hours to make sure there are no ill effects. Even non-poisonous mushrooms can cause allergic reactions in some people.
Keep all mushrooms separate when you collect them to avoid any cross contamination.
Never eat a mushroom if you are unable to identify it.