Determining whether a mushroom is poisonous or not can be a difficult task. There are thousands of species of mushrooms, many of which look similar to the naked eye. While some mushrooms are delicious and safe to eat, others contain toxins that can cause severe illness or even death if ingested. Being able to identify poisonous mushrooms is an important skill for foragers and wild mushroom enthusiasts. Here are some tips on how to tell if a mushroom is poisonous.
Examine the mushroom’s physical features
One of the first steps in identifying whether a mushroom is poisonous is a visual examination of its physical features. While some poisonous mushrooms may appear very similar to edible varieties, there are certain characteristics that can provide clues:
- Color – Some toxic mushrooms have distinctive colors like red (Amanita muscaria) or orange (Jack O’Lantern). However, don’t rely on color alone as some poisonous mushrooms are brown like edible ones.
- Shape – Irregular shapes with bulges, pits, or scales may indicate a poisonous mushroom.
- Gills – Poisonous mushrooms often have gills instead of pores under the cap. However, some toxic gilled mushrooms resemble edible ones.
- Spore print – Making a spore print can reveal the mushroom’s spore color which helps narrow identification. For example, pink or red spores often mean it’s toxic.
- Smell – A foul or unpleasant odor can be a warning sign of poison.
- Location – Knowing what mushrooms grow in your area can help rule out poisonous lookalikes.
While physical characteristics provide clues, mushrooms should never be consumed based on appearance alone. Always confirm a mushroom’s identity before eating.
Understand the mushroom’s habitat and seasonality
Paying attention to where and when a mushroom grows can also aid in determining whether it’s poisonous:
- Habitat – Many toxic species prefer specific habitats. For example, the death cap mushroom grows near hardwood trees, while the destroying angel mushroom grows in forests near pine trees.
- Season – Poisonous mushrooms have certain seasons. Morels only grow in spring while fly agarics grow in late summer and fall.
- Associations – Some toxic species grow among or close to certain edible species.
If a mushroom seems out of place for when or where it’s growing, proceed with caution. Consult resources to learn your local mushrooms’ preferred habitats and fruiting times.
Beware of lookalikes of edible varieties
Many poisonous mushrooms closely resemble edible species. Some examples of toxic lookalikes include:
- The deadly galerina mushroom looks similar to the edible honey mushroom.
- The toxic false morel resembles the edible true morel mushroom.
- The poisonous jack o’lantern mushroom can be mistaken for the chanterelle.
- The fool’s funnel cap passes for the edible funnel chanterelle.
These lookalikes often grow in the same habitats and seasons as their edible counterparts. Scrutinizing subtle differences in appearance and always verifying identity can prevent accidental poisonings.
Learn to recognize warning signs of the most poisonous species
There are some highly toxic mushroom species all foragers should know how to identify. Learning to recognize the following mushrooms could save your life:
- Death cap – Has a greenish-yellow cap, white gills, sac-like cup at base of stem, and often grows near hardwood trees.
- Destroying angel – White mushroom with distinct skirt-like ring on the stem and grows in forests near pine trees.
- Autumn skullcap – Has a brown cap with tan scales and resembles edible mushrooms like honey fungi and puffballs.
- Fool’s mushroom – White, bell-shaped caps growing in overlapping clusters on tree stumps and roots.
- Podostroma cornu-damae – Reddish-brown caps with whitish stems, growing in clusters on hardwood logs.
Learning to identify the most dangerous species where you forage can help you steer clear of poisoning.
Consider performing field tests, but use caution
There are some traditional field tests that can provide additional warning signs of possible toxicity:
- Latex or milk test – A milky or colored latex exuded from cut flesh may indicate poison.
- Stain test – A mushroom that stains or changes color when bruised or injured may be toxic.
- Flavor test – A bitter, sour, or peppery taste can signify a poisonous mushroom.
However, field tests are not definitive identification. Only an expert mycologist should consume mushrooms after performing similar tests, and even then great caution is needed. The safest approach is to avoid eating any questionable mushrooms.
Submit samples to an expert mycologist
If you are uncertain about the safety of a mushroom you wish to consume, having an expert identify it is crucial. Many local mycological societies offer mushroom identification services. To have a mushroom properly identified:
- Photograph the mushroom in its natural habitat, including close-ups of cap, gills, stem, base, etc.
- Note any bruising/staining and ecosystems nearby where it was foraged.
- Harvest a complete, fresh sample. Place in paper (not plastic) bag.
- Keep samples refrigerated until you can submit them to an expert mycologist.
Having an expert examine the mushroom helps remove any doubt about its edibility. Proper identification protects against poisoning.
Avoid relying on folklore methods
There are many untrue folklore methods for determining if mushrooms are poisonous, which should be avoided:
- Silver spoon – Tarnishing a silver spoon does not confirm toxicity.
- Garlic test – No evidence that garlic changing color reveals poison.
- Insect consumption – Insects eating a mushroom does not guarantee its edibility.
- Cooking – Poisonous mushrooms can’t be made safe by cooking.
These and other folklore methods provide no reliable guidance on a mushroom’s safety. Stick to verifying identity using skilled mycologists.
Use multiple identification resources
Accurately identifying mushrooms requires consulting multiple scientific resources such as:
- Field guides with detailed mushroom descriptions and images.
- Mobile apps with photos, habitat/seasonality details of regional mushrooms.
- Websites of mycological societies with identification tips and databases.
- Reference books and scientific papers on toxic fungi.
Cross-check characteristics in multiple resources to confirm IDs. Beware sources with limited or outdated information that could cause misidentification.
Exercise extreme caution with wild mushrooms
When dealing with wild mushrooms, it’s critical to exercise caution:
- Assume every mushroom is toxic until you can confirm it’s edible.
- Only pick and eat mushrooms you can identify with 100% certainty.
- Do not eat raw wild mushrooms – cook thoroughly first.
- Only consume a small portion initially to check for allergic reactions.
- Avoid picking mushrooms growing in polluted areas.
Consuming even a portion of a toxic mushroom can have devastating consequences. Absolute certainty of identification is essential before eating any wild mushrooms.
Learn the different mushroom poisoning syndromes
Being aware of the toxic effects associated with various mushroom poisoning syndromes can aid in seeking prompt treatment if poisoning occurs:
| Syndrome | Onset Time | Symptoms |
|---|---|---|
| Amatoxin | 6-24 hours after ingestion | Nausea, vomiting, diarrhea, liver and kidney failure |
| Orellanine | 2-3 weeks after ingestion | Kidney failure, thirst, frequent urination |
| Muscarine | 15-60 minutes after ingestion | Salivation, sweating, tears, diarrhea, breathing difficulties |
| Coprine | 30 minutes-2 hours after ingestion | Facial flushing, headache, vomiting after alcohol consumed |
Seeking rapid medical care and bringing identification materials can help healthcare providers determine appropriate treatments.
Keep pets and children away from wild mushrooms
Take precautions to keep pets and children from eating unknown mushrooms, as they are at high risk of poisoning:
- Supervise pets when outside and don’t allow them to forage or ingest mushrooms.
- Remove mushroom fruiting bodies from yards where kids and pets could access them.
- Teach children never to touch, pick, or eat any mushrooms without adult supervision.
- Contact Poison Control immediately if a child or pet is suspected of eating a wild mushroom.
Quick action is essential to treat poisoning and prevent serious harm to children and pets who ingest unknown mushrooms.
Learn foraging etiquette
When collecting wild mushrooms, follow some basic etiquette rules:
- Never trespass on private property or protected conservation areas.
- Only harvest a few mushrooms, leaving the majority to disperse spores.
- Cut mushrooms off at base instead of pulling them out of the ground.
- Use a mesh bag to allow spores to spread as you forage.
- Help educate others on foraging etiquette when witnessing poor behavior.
Being a responsible steward of the environment ensures mushroom foraging remains sustainable.
Conclusion
Determining if a mushroom in the wild is toxic requires a combination of strategies – careful study of physical features, understanding habitat and seasons, identifying lookalikes, recognizing deadly species, field tests, and expert identification. However, when foraging for wild mushrooms, there is no room for guesswork or folklore. Only eat mushrooms that can be identified with 100% certainty as edible varieties. Applying caution, using multiple scientific resources, and verifying with experts helps avoid tragic poisonings from toxic fungi.
