There is no definitive way to identify the difference between poisonous and edible mushrooms. There are some factors to clue you in, but these are not foolproof. You have to use a mushroom reference guide and contact your local mycological specialist. That said, the cap, stem and color of the mushroom can provide you a good idea about its toxicity.
What is the Best Way to Know the Difference between Poisonous & Edible Mushrooms?
The surest way to know the difference between edible and poisonous mushrooms is to confer with a mycological expert. Take a photo of the mushroom and show it to the expert. When you take the photo, capture several vantage points. Get a close up of the cap, gills, stem and the soil. Also take a picture of the surrounding area so the mycological expert can see every detail.
How Do You Identify Different Mushroom Species?
Your first identification clue will be the time of year it is. Make note if it’s spring, summer or fall. When foraging for mushrooms in the woods or spotting a patch in your yard, consider the following identification criteria:
- Is there a distinct scent?
- Does the mushroom change color when cut or bruised?
- What kind of texture, shape, size and color is on the cap?
- What kind of texture, shape, size and color is on the stem?
- Is a skirt or ring present on the stem? Are there any other markings?
- Are there pores, gills or spikes on the underside of the cap?
- If there are gills, how close are they? Do the gills fork? Do the gills connect to the stem?
- Does the cap’s underside feel soft, pliable and brittle?
- What is the texture of the flesh on the cap and stem? Are there two different textures?
Are There Typical Characteristics between Poisonous and Edible Mushrooms?
Although there aren’t any definitive rules to distinguish between poisonous and edible mushrooms, there are a few characteristics to note. Color and shape should be your first observation. After that, everything else will be easier to identify. There are four categories:
Toxicity is the leading characteristic between edible and poisonous mushrooms. You can identify these either by the smell, appearance or color changing ability of the mushroom. These are the four types and what happens in a reaction:
- Protoplasmic Toxins – These eventually cause organ failure due to how it destroys body cells.
- Neurotoxins – Hallucinations, excessive sweating, convulsions, spastic colon activity, coma and even depression are just some of the neurological symptoms that can result after ingesting mushrooms with this kind of toxicity.
- Gastrointestinal Toxins – Cramps, nausea, diarrhea, vomiting and abdominal cramps come about shortly after eating some poisonous mushrooms.
- Disulfiram-like Toxins – Of all the toxins possible in mushrooms, this is the least severe. Symptoms only come on upon drinking alcohol within three days of consumption. Even if this is the case, there will be a short-lived toxic acuity.
Habitat will also be a major factor in determining toxicity. For instance, some mushrooms are poisonous when growing on cedar while others are safe developing in the roots of a dead elm tree. But they can also grow on lawns, open paddocks and orchards.
The season also determines whether a mushroom is poisonous or not. As an example, Amanitas that appear in summer and autumn on woodland floors are quite toxic and you should avoid them at all costs.
3. Physical Characteristics
How a mushroom appears is often the dead giveaway to distinguish between poisonous and edible mushrooms. The first tell-tale sign is the cap and how it looks. Edible mushrooms generally have smooth caps that come in some variation of white. Poisonous ones will have warts or scales with varying colors on the cap.
Cap Shape & Accessories
The shape of the cap is also important. Edible mushrooms look like a bun or have a convex-looking cap. And yet others, like Chanterelle Mushrooms, have a waviness to the cap, appearing concave or even trumpet-shaped. Poisonous mushroom caps will also be convex, but these flatten out as they mature.
Poisonous mushrooms will often have a ring on the underside of the cap that connects to a fat, bulbous stem. Edible mushrooms have thin, narrow stems that go into the soil and gradually get thicker as the stem travels to the cap.
The spore pattern that disperses from the mushroom will also be a surefire way to determine a mushroom’s toxicity. The color can range from white to black and many other shades. All you have to do is take a piece of dark or white paper and let the mushroom sit for several hours, gill side down.
If you see white spores, chances are, it’s poisonous. But it’s best to show this to a mycological expert or use a reference guide to be sure.
In regards to the gills, they can give some clues to a mushroom’s propensity to be poisonous. Most edible mushrooms will have gills that only attach to the cap, even if you remove the stalk. Gills on a poisonous mushroom will attach to the stalk and stay there even if you remove it from the base.
Younger edible mushrooms will have a pink color to the gills that transforms into brown or black as it matures. You will see white gills that stay the same color throughout its life span in mushrooms that are toxic.
Scent is a decent determiner to help decipher between edible and poisonous mushrooms. However, this isn’t foolproof. Since there are some poisonous ones that smell lovely and sweet, you can’t rely on this alone.
But, as a guideline to help with identification, the general rule is that if they smell earthy or fruity, they’re edible. Mushrooms that stink or have no odor may very well be poisonous. The best way to get a good whiff is by crushing the cap with a gloved hand.