Note: Some wild mushrooms are poisonous, and they may resemble edible species. Eating them may make you sick or kill you. It is your responsibility to identify any wild food with 100% certainty before you eat it.
The author of this web site is not responsible or liable for any ill effects that result from visitors to this web site ingesting wild mushrooms or plants.
What Are Mushrooms?
A mushroom is the fruit of a fungus. Its purpose is to disperse spores, microscopic single cells that can grow into new fungi.
The fungus looks like a series of branching threads infiltrating the soil or leaf litter, or in the wood of living or dead trees. (These higher fungi, which produce mushrooms, consist of many cells. Single-cell lower fungi, which don't produce mushrooms, aren't covered here.)
Mushrooms in different groups take different forms because they have diverse strategies for disseminating spores. These basic forms, many of which you'll find on the Mushrooms Home Page, let you take the first step toward identifying mushrooms you find to species, which is essential before you eat them.
Because of lingering superstitions and prejudices, people overlook mushrooms' essential roles in our environment.
Some fungi interconnect to a tree's microscopic root hairs, taking glucose (simple sugar) in exchange for the minerals and water the fungus obtains from the soil, a symbiotic (living together) relationship called commensualism. The fungus may also create plant hormones that stimulate the tree to grow. About 80% of trees depend on these overlooked fungi, which scientists call mycorrhizal.
Saprophytic fungi grow in dead wood or dead organic material, break it down, and return nutrients to the soil so new life can flourish, an essential function for our ecosystems.
Other fungi are parasitic, attacking living trees and sometimes killing them, paving the way for the saprophytic species and renewal (some parasitic fungi also become saprophytic after they kill the tree).
Some mushroom species are very easy to identify (the chicken mushroom or sulfur shelf, the giant puffball, morels, and the chanterelle are considered so obvious that people call them the foolproof four). Others are quite difficult. Some species have poisonous look-alikes, others are quite distinct and have no poisonous relatives. Learn a small number of the most unmistakable species at first, and check with an expert before you eat any wild mushrooms.
If you don't know any local experts who can teach you about your regional mushrooms, join a mushroom club. The North American Mycological Association (NAMA) has a list of regional organizations and other useful information. I'll also continue adding resources to my GreenLinks' mushroom section as they become available.
Deadly Edibility Tests
Some people mistakenly claim that if a clove of garlic or a silver coin you cook with wild mushrooms doesn't turn black, the mushrooms are safe. This is completely false, but since only about 1 out of 100 wild mushrooms can kill you, and those who died because from this method aren't around anymore to dispute it, the myth persists.
Some people from other countries follow their folk traditions and learn a small number of mushrooms by sight from their elders, sticking to those species for years. But when they come to America, they don't always recognize poisonous look-alikes absent in the old country, and these nonscientific mushroomers sometimes poison the whole family. Different species grow in widely separated geographical regions.
You can see the color of a mushroom's microscopic spores by making a spore print. Cut off and discard the stem if the mushroom has one. Place the cap on heavy white or black paper (or a glass slide if you're going to use a microscope) with the gills or pores (or other spore-producing surface) facing downward. Cover with a bowl or cup to block air currents, and leave 6 hours to overnight.
Remove the bowl or cup and the mushroom. If the mushroom was fresh, and mature enough to be making spores, you should see a radial pattern of powder on the paper (you can preserve the spore print with fixative spray from an art store, or hair spray).
Mushroom Cap on White Paper Under a Drinking Glass Creating a Spore Print
The spore print's color is an important identifying characteristic, although it's insufficient by itself to identify any mushroom. But if, for example, your spore print is white, and your mushroom book says the species you thought you had collected has brown spores, your identification is wrong.
Mushrooms Demystified by David Aurora is the best, most comprehensive general guide. Because it's too heavy to carry into the field, you should also get The Audubon Society Field Guide to North American Mushrooms by Gary Lincoff. It's the most useful field guide.
These books still don't cover all the mushrooms you'll find. After you've used them for a while, you'll want to look for regional guides for mushrooms of your locality, and books that cover specific groups of mushrooms.
You'll still never be able to identify every mushroom you find (especially LBMs and LWMs—little brown mushrooms and little white mushrooms, which are nearly impossible to identify), but you'll improve, and you'll eventually be able to eat the mushrooms you know best in safety.
Put mushrooms in paper or wax paper bags—never plastic, which makes mushrooms spoil. A marking pen for writing on the bags lets you put the same mushrooms together without having to look inside each bag every time you find a new specimen.
A basket will prevent a large collection of specimens from being crushed. (Russian folklore advises against bringing a basket because the mushrooms will catch on to your intentions and hide!)
A pocket knife helps cut off mushrooms cleanly and trim away the dirt. If leaves are piled high, a walking stick may help you push them away.
Sneakers or hiking shoes are good for foraging. Sandals leave you vulnerable to poison ivy and thorns. Long pants and sleeves provide additional protection unless it's too hot.
A compass and map are good in unfamiliar territory. A whistle can also be helpful: Whistle once to let others know where you are, twice to call them over to an interesting find, three times for emergencies.
Don't forget drinking water and a snack.
Use different bags for different species. Never mix poisonous or unknown mushrooms with edible species.
Make sure you collect the entire mushroom, including any underground parts, which sometimes hold vital identification information.
Check for bugs (especially if you're a vegetarian). Discard mushrooms with maggot tunnels inside. Those mushrooms are decomposing, and rotten food can make you sick.
Trim the soil off mushrooms before putting them in bags. This is much easier than letting the gills or pores fill with dirt, then trying to clean them at home.
Refrigerate mushrooms as soon as you get home. If you put poisonous or unknown species in the refrigerator, make sure no one in the household is going to eat them accidentally.
Eat small amounts of new species at first. Anyone can be allergic or sensitive to any new food. Keep 1 mushroom uncooked and refrigerated just in case professional identification becomes necessary.
Avoid eating mushrooms contaminated with pesticides, herbicides, or other poisons. Railroad right-of-ways are especially contaminated, as are areas within 50 feet of heavy traffic or highways.
Where and When to Look
Mushrooms can be anywhere, from empty lots in Manhattan to neighborhood lawns and street trees, to meadows and woods. In eastern North America, the best season is the fall, although spring and summer are also good. A couple of edibles even may appear in the winter.
The most mushrooms appear after heavy rain. Some come up the next day, others a few days later.
Refrigerate mushrooms to store them short-range, and prepare them as soon as possible. They are very perishable. A mushroom that's wholesome one day may be filled with maggots the next day.
Clean mushrooms with a soft mushroom brush or a toothbrush. To minimize sogginess, use as little water as possible, especially if you're planning to sauté, a process that doesn't work with wet food. (The more dirty the mushrooms are, the more water you'll have to use.) Trim away any bad or hard parts with a paring knife.
Cooking methods depend on the mushrooms. Some are good sautéed, baked, steamed, or simmered in soups or sauces. Some species, especially those with high water content, aren't good sautéed, but need to be simmered or steamed. The least flavorful species improve greatly if you first marinate and then bake them.
Wild mushrooms provide the best non-animal source of vitamin D. Some species provide B vitamins, and a few even contain vitamin C.
In 2005, a new testing method found that wild mushrooms provide way more of the antioxidant ergothioneine than any other food. Additional studies show that 2 commercial species (and most likely wild mushrooms as well) are also good sources of polyphenols, antioxidants that reduce cancer risk and may slow aging.
Mushrooms contain chitin, a non-soluble protein that precipitates bile in the large intestine so it is eliminated from the body, rather than being reabsorbed, forcing the body to make new bile. It does this by breaking down cholesterol, improving cardiac health. Traditional Chinese herbalists knew of this effect for centuries, saying that eating mushrooms cleans the arteries.
Along with chitin, mushrooms are rich in beta-glutan, the heart-healthy carbohydrate that accounts for oats' well-publicized association with lower rates of heart disease.
Some wild mushrooms are delicious and safe, others are as tasteless as some of my jokes. Some taste so bad that one piece will ruin a recipe, and others are as tough as wood or leather.
As there are varying degrees of edibility, there are different ways to poison yourself with wild mushrooms. Whatever the symptoms, victims should seek medical care immediately.
Many poisonous mushrooms cause varying degrees of gastrointestinal irritation. Symptoms such as abdominal pain, vomiting, and diarrhea occur within an hour or two of eating the mushrooms, and the victim eventually recovers.
The worst poisoning occurs when symptoms don't occur until 6-12 hours after eating the mushroom (see Amanita Overview) because in addition to severe gastrointestinal distress, such poisoning may lead to fatal liver and kidney destruction.
Some mushrooms affect the central or peripheral nervous system, causing sweating, dizziness, weakness, or hallucinations. Of course, some people purposely take hallucinogenic mushrooms to get high, which is illegal, and if they don't identify them correctly, as often happens, they can poison themselves.
Some mushrooms cause adverse reactions in some people in combination with alcohol consumption. Some mushrooms contain unknown toxins. And some people experience allergies or other adverse reactions after eating mushrooms that are harmless to other people. This is why you should eat small quantities of any new food the first time you consume it.
By Dan Gil