What kinds of poisonous mushrooms are found in Colorado?

If you spend time outside, you’ve probably asked this question at least once. Poisonous mushrooms definitely have an infamous reputation.

Below, I have listed common poisonous mushrooms you can expect to find in Colorado. But in NO WAY is this a complete listing of dangerous fungi. There are thousands of mushrooms in North America, so reviewing and writing about every toxic species is nearly impossible.

IMPORTANT: I can’t stress enough that you should NEVER eat a mushroom you find. As you will see below, there are many poisonous types, and some species will kill you. So stay safe, and don’t eat any wild mushrooms unless you are with a mycologist (mushroom expert)!

11 Poisonous MUSHROOMS in Colorado:

#1. Lilac Bonnet

Mycena pura

Also called Lilac Mycenas or Lilac Bellcaps.

The caps begin as lilac or purple and bell-shaped but flatten and fade to other shades, including whitish, yellowish, pinkish brown, or reddish as they age.
The stems are smooth and white or flushed with the cap’s color.

These toxic mushrooms are one of the most beautiful fungi in Colorado. Their unusual lilac coloring makes them a treat for hikers and adventurers to spot as they grow on the ground of coniferous and hardwood forests. Their radish-like odor can also help you to distinguish them.

Despite all their charm, Lilac Bonnets are fun to look at but not to eat. These mushrooms contain several toxic compounds.

Lilac Bonnets contain sesquiterpene, which can cause vomiting, cramps, and diarrhea, and strobilurin, which is often used in agricultural fungicides.

They also contain small amounts of muscarine, which causes symptoms like blurred vision, excessive sweating, increased salivation, and abdominal issues.

Interestingly, Lilac Bonnets weren’t always thought to be toxic. It’s possible to find older mushroom field guides that list Lilac Bonnets as edible.

#2. Funeral Bell / Deadly Skullcap

Galerina marginata

The caps are usually pale yellow, brown, or orange, depending on age and weather, and are generally darker colored toward the center.
They have tan, fairly crowded gills and pale, thin flesh that darkens with age.

This aptly named toxic mushroom contains the same compounds as the famous Death Cap mushroom. These deadly compounds are known as amatoxins, and consuming them can result in SEVERE liver damage.

It is believed that about ten fatal poisonings in the last century can be attributed to the Funeral Bell.

This mushroom is often mistaken by foragers looking for edible or hallucinogenic mushroom species.

Foragers sometimes refer to these and other similar-looking mushrooms as LBMs or “little brown mushrooms” because they can be difficult to distinguish.

One of the identifying features of this poisonous mushroom in Colorado is that it grows on decaying wood. Funeral Bells most frequently grow on conifer stumps and logs but are occasionally spotted in deciduous forests or even in open fields where woodchips have been dumped.

#3. Fly Agaric

Amanita muscaria

The caps are scarlet or dark orange with white, wart-like spots, which may wash off as mushrooms mature.
The stalk is white and brittle with shaggy rings of scales, a bulbous base, a cup-like veil near the base, and a skirt-like veil near the top.

The Fly Agaric is arguably the most iconic poisonous mushroom in Colorado.

This colorful toadstool has an equally colorful history. The name “fly” may come from the mushroom’s historical use as an insecticide in parts of Europe. It contains ibotenic acid, which attracts and kills flies.

However, some people believe the name refers to the hallucinations that result from its consumption. This mushroom once saw widespread use in religious ceremonies.

Through the ages, this mushroom has also been wrapped up in fairytales and folklore. You may remember it as the mushroom Alice is given to eat in Alice in Wonderland or as the mushrooms in the Super Mario Bros games.

Fly Agarics grow in symbiotic associations with trees and can be found in delicious and coniferous forests in temperate and boreal regions.

While it is poisonous, deaths due to consuming Fly Agaric are rare.

#4. Sulphur Tuft

Hypholoma fasciculare

The caps are 2–6 cm (0.8–2.4 in) in diameter.
Their coloring is light yellow but darkens to greenish as they mature.
This fungus grows in clusters of long-stalked, bell-shaped mushrooms.

Look for Sulphur Tuft Mushrooms in Colorado on fallen logs, tree stumps, and buried roots in deciduous forests. This fungus is hardy and thrives in many environments. In fact, you can often find Sulphur Tufts even in places where other mushrooms won’t grow.

They look similar to some varieties of edible mushrooms, but you should NOT handle or eat Sulphur Tufts. They are poisonous to humans, whether raw or cooked. This fungus causes vomiting, diarrhea, stomach cramps, kidney disease, and, in rare cases, death.

#5. Violet-toothed Polypore

Trichaptum biforme

The caps are 1-7.5 cm (0.4-3 in) wide.
Their shape is an irregular semicircle, similar to a seashell.
The coloring of this fungus is shades of brown with violet, purple, or lavender rings near the edges.

If you spot a mushroom in Colorado that looks like a clamshell, it’s likely a Violet-toothed Polypore! This species can be identified by its shell-like shape and striped purple coloring. It grows in stacked clusters on rotting logs.

Interestingly, Violet-toothed Polypore is known to only grow on decaying aspen and poplar trees. So, if you live near a forest with those species, you’ll likely find this poisonous mushroom!

Violet-toothed Polypore is inedible and causes stomach problems and dehydration. Make sure to keep your pets away from this toxic mushroom, as it’s particularly poisonous for dogs.

#6. False Morel

Gyromitra esculenta

The caps are brain-like, red-brown, wrinkled, and usually wider than tall.
They usually have more solid stems with small air pockets than true morels, which have hollow stems.

The False Morel is one of the more controversial poisonous mushrooms in Colorado.

False Morels contain a compound called Gyromitrin, which the human body metabolizes into Monomethylhydrazine, a major component in rocket fuel.

This compound can damage the liver, central nervous system, and occasionally the kidneys. Victims may experience diarrhea, vomiting, dizziness, headache, and even death.

Given this horrible effect, it will probably surprise you to learn that part of its Latin name, esculenta, means edible!

In order to eat these funky-looking mushrooms, people use specific cooking techniques. These may include blanching the mushrooms outside or in a well-ventilated area, as Gyromitrin can become airborne during cooking.

Unfortunately, several instances of poisoning from False Morels, including fatalities, have occurred. It’s best to leave these to the experts! DO NOT TRY EATING THIS MUSHROOM.

False Morels usually grow in deciduous and coniferous forests in temperate regions. They often thrive in areas with sandy soil, and in coniferous forests, they are frequently found around pine trees.

#7. Green-spored Parasol

Chlorophyllum molybdites

The caps are 8-30 cm (3-12 in) in diameter.
This mushroom is white or off-white with irregular brown spots and warts.
The gills are visible around the edges of the top and very prominent on the underside.

This is the most frequently eaten poisonous mushroom in Colorado!

Green-spored Parasols bear an unfortunate resemblance to several edible fungi, which means they’re often eaten by mistake. In addition, this fungus causes severe stomach symptoms such as vomiting, diarrhea, and colic.

Unfortunately, this mushroom is common on lawns and pastures, putting children and pets at greater risk for poisoning. Please keep them away from these mushrooms!

Green-spored Parasols grow directly from the ground instead of from tree logs or other decaying wood. We recently had a cluster pop up after we had new mulch put down. The spores are often present in soil or mulch and can remain dormant until the next fruiting season.

#8. Poison Pie

Hebeloma crustuliniforme

The caps begin as convex but flatten with age and are off-white to pale, darker towards the center.
The stems are off-white with a slightly wider base, and the whole mushrooms have a firm, white inner flesh.

The name Poison Pie should be enough to keep any forager away from this toxic mushroom. But its other common name, Fairy Cakes, is a bit misleading!

Though less deadly than some species like the Death Cap (Amanita phalloides), Poison Pie is not a mushroom you want to snack on.

Consuming Poison Pie mushrooms can result in abdominal pain, vomiting, and diarrhea.

Thankfully, Poison Pies are rather unappealing anyway. They have strong radish-like aroma and bitter flavor.

Poison Pies have symbiotic relationships with various tree species. You may find them growing singly or in small groups in deciduous or coniferous forests.

#9. Common Earthball

Scleroderma citrinum

They have round, flattened fruiting bodies with hard, scaly, and yellowish to yellow-brown surfaces and white inner rinds that stain pink when sliced.
The inner spore mass is white on young mushrooms but turns dark purple to purple-black with age, spreading outward from the center.
They have no real stem, but you may find some mycelium threads running into the soil.

These mysterious toxic mushrooms look more like potatoes than fungi at first glance! These odd-looking mushrooms have an unusual method of spore dispersal, too.

Rather than releasing spores from their gills like many mushrooms, these mushrooms eventually form a split in their top as they mature. Each time raindrops, animals, or anything bumps the mushroom, clouds of spores will be released through the slit, eventually leaving just a hollow rind.

You can find Common Earthballs growing in deciduous and coniferous forests and heaths. They do best in soft, sandy, acidic soil.

While not deadly, this mushroom is responsible for many poisonings each year.

It’s commonly confused with Common Puffballs (Lycoperdon perlatum), which are edible mushrooms.

#10. Saddle-shaped False Morel

Gyromitra Infula

Their surface may be smooth to somewhat bumpy and irregular, variable in color, and can be tan to yellowish brown, reddish brown, or dark brown.
The stems are roundish or slightly compressed and are usually white or pink-tinged with white mycelium near the base.

These toxic mushrooms get their name from their tell-tale, two-lobed saddle shape.

Though there are reports of people eating these mushrooms after boiling, most experts conclude Saddle-shaped False Morels are toxic. They contain contain the compound Gyromitrin.

Interestingly, the human body metabolizes Gyromitrin into Monomethylhydrazine, a significant component in rocket fuel.

Saddle-shaped False Morels usually grow in Colorado in boreal, montane, or coastal forests. They often grow in close associations with several specific tree species, including Western White Pine, Black Spruce, Douglas Fir, Western Hemlock, Balsam Poplar, and Paper Birch.

You may spot Saddle-shaped False Morels growing singly or in small groups, often on rotten wood. It’s also commonly found growing on packed ground, like along rural roads or in campgrounds.

#11. Panthercap

Amanita pantherina

The caps are dark brown to slightly red-brown with white, wart-like spots with white inner flesh.
The stems are white with a skirt, a shaggy texture below the skirt, and a bulbous base.

A taste of this toxic mushroom in Colorado can cause hallucinations, retrograde amnesia, delirium euphoria, dysphoria, and synaesthesia.

Panthercaps contain the toxic compounds muscimol and ibotenic acid. While they do cause hallucinations, their effects are likened more to taking overdoses of Z-drugs like Ambien rather than that of classic psychedelic mushrooms.

While it may not be fatal, consuming Panthercaps would be unwise. The concentration of ibotenic acid can vary significantly from mushroom to mushroom, resulting in diarrhea, vomiting, and severe sweating, leading to dehydration.

While it is still disputed, there are also some claims that the Panthercap is one of the mushrooms that Viking warriors “berserkers” chewed before battle. It is claimed that the rage the warriors displayed was due to the mushroom’s side effects.

Usually, you can find Pantercaps growing in Colorado in deciduous woodlands, though they occasionally grow in coniferous forests as well.

11 POISONOUS Mushrooms found in Colorado! (2025)