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The ‘Shroom Zone: Colorado’s fabulous fungi

Article by Bob Berwyn

Mushrooms – August 2000 – Colorado Central Magazine

WITH NAMES LIKE red raspberry slime, elegant stinkhorn, and stinky squid, what’s not to love about mushrooms?


Not all the mushrooms in the Rocky Mountains have been identified and classified. While there are many species that are edible, some mushrooms can make you sick, and a few can kill you. The author and the publisher do not accept responsibility for the identification of any mushrooms or for the consequences of eating them.

And whether you love ’em or hate ’em, it’s peak season for Colorado’s fabulous fungi. If you’ve been hiking in the woods lately with your eyes half open, you’ve probably noticed them sprouting under trees and on rotting logs, hiding in clumps of grass or under pine cones, growing in a dazzling variety of shapes, sizes, and colors.

Where do they come from? Why do they appear so suddenly and profusely, only to vanish again a few days or even just hours later?

Ancient Greeks thought they sprouted where Zeus’s lightning bolts hit the ground, since they appeared after summer thunderstorms. In the Middle Ages, the circular patterns formed by some mushroom species were called “fairy rings,” thought to be the work of elves.

More recently, some mystics and spiritualists have espoused theories that their spores arrived from outer space riding piggy-back aboard meteorites, helping to spread a universal consciousness throughout the cosmos via the mind-altering qualities of the hallucinogenic mushroom species like psilocybe.

In fact, fungi are about as down-to-earth as you can get. Together with bacteria, they are primarily responsible for recycling much of the earth’s organic waste, converting dead wood into nutrient-rich detritus, for example.

[Amarita muscaria — beautiful but poisonous]


Fungi are neither plant nor animal. Biologists have given them their own kingdom, since they lack the chlorophyll that allows plants to convert solar energy directly into readily usable carbohydrates. Instead, like animals, they depend on organic material for nutrition.

The kingdom of fungi includes thousands of microscopic species, including varieties that are responsible for fermenting grape juice and causing athlete’s foot. Other micro-fungi have allied themselves with blue-green algae to form lichen — a so-called dual organism that literally eats the rock it lives on, breaking it down into its mineral constituents.

But the fleshy macro-fungi — the mushrooms that we buy in the grocery store and find growing along the trail and in our lawn, are the real stars of the fungal variety show.

The caps that grow above the ground are the fruiting bodies of a web of underground fibers called hyphae. The strands can extend in every direction for hundreds, and even thousands of feet.

Given the right combination of rain and temperature, the mycelium forms tiny pinheads that can grow into a 2-pound mushroom within a few days. The purpose, of course, is procreation — a single mushroom cap can release millions of microscopic spores into the air in its short life. Under the right conditions, the spore sprouts into a new thread. When it meets with a compatible strand, they join together and begin forming a new mycelium, starting the cycle anew.

Some of the fruiting bodies are edible — and delicious. A few are deadly poisonous and there are thousands of species still awaiting identification and classification. But one thing is certain: Fungi form an integral and crucial part of every forest ecosystem by forming symbiotic relationships with plants.

Without them, the forest landscape would probably not exist as we know it.

The strands of the mycelium intertwine with the root tips of trees and plants, sheathing them and in some cases even penetrating the cell walls of the roots. The two organisms merge in what is called a mycorrhizal relationship. The arrangement enables an exchange of nutrients. The fungi increase the absorptive capability of the root system many-fold and pass minerals along to the plant, receiving sugars and carbohydrates in return.

[Raspberries & Cream (Hydnellum peckii) is not edible, despite its appetizing name]

The single-celled threads grow together to form a mycelium — the subterranean bulk of the fungal organism. The cottony white mass is sometimes visible in damp forests on rotting stumps or among piles of wood chips. Some biologists now claim that the mycelium of some fungal communities may be the largest single living organism on the planet.

Almost all green plants partner with fungi. Besides exchanging nutrients, the antibiotic properties of some fungi seem to protect tender root tips from bacterial attack. That shouldn’t be surprising, since some of the most potent antibiotics — including penicillin — were originally derived from fungi.

Other species of fungi attack and parasitize trees, eventually killing them.

BUT THAT IS ALSO A PART of the ecological process of a forest ecosystem, creating snags that can be hollowed out by cavity nesters. Still other varieties break down dead wood and leaves by digesting the tough cellulose and lignin and returning it to the soil in a form that can be used by growing plants.

“They’re the recyclers of the natural world,” says Marilyn Shaw of the Colorado Mycological Society. “They clear the forest of dead wood. Without them, we’d be up to our eyeballs in dead branches.”

In the Pacific Northwest, land managers have formally recognized the importance of fungi to forest ecology by including a mycological component in the regional forest plan, aimed at preserving crucial habitat for the endangered spotted owl.

In the process, mycologists collected thousands of species and even found many new species.

“It was like a treasure hunt out there,” says Michael Castellano, who helped put the plan together. “Less than 10% of the species we found have been identified. We got some great information on range and distribution,” he says, adding that at least some of the information could be used by other forest planners around the country as they update their plans on a periodic basis.

About 10 or 15 years ago, Castellano developed a technology for inoculating seedlings with spores from mycorrhizal species to help ensure good growth. That technique is in widespread use today, and has even found commercial applications.

Mycorrhizal fungi play an important role in the health of old-growth forests, but there’s an even more direct connection to the spotted owl, according to Castellano. Among the spotted owl’s favorite prey is the northern flying squirrel. As it turns out, the squirrel’s favorite food is an underground variety of fungus in the truffle family, Castellano says.

The health of forest fungi is also at issue in central Europe, where large swaths of forests have suffered severe declines. Some long-term studies show that fungal diversity in some areas has been halved in the past 50 years. It’s not yet certain if failing forest health — blamed in part on acid rain — led to the decline of the mushrooms, or if the acid rain directly affected the fungi, and thereby subsequently impacted the forests. Some researchers say over-harvesting may be to blame, but by other accounts, even poisonous varieties that aren’t commonly picked are declining.

Into the ‘shroom zone

[The Hawk’s Wing (Hydnum imbricatum) is fairly common and has a strong flavor]

The single-celled threads grow together to form a mycelium — the subterranean bulk of the fungal organism. The cottony white mass is sometimes visible in damp forests on rotting stumps or among piles of wood chips. Some biologists now claim that the mycelium of some fungal communities may be the largest single living organism on the planet.

Fungi grow almost everywhere and nearly all year round. But in our area, the underground mycelium seems to be more or less dormant during the colder months.

With enough spring rain and favorable temperatures, mushrooms in the Rocky Mountains begin fruiting in April and May at lower elevations. Some mushrooms have even adapted to life at the edge, sprouting just behind the receding line of melting snowbanks. The season ends when the first hard frosts of autumn begin to kill the fruiting bodies.

The ‘shroom zone encompasses nearly all of Colorado, from the stream banks of rivers out in the plains, up to the tundra along the Continental Divide. But the spruce, fir and pine forests of the subalpine zone, between about 7,000 and 10,000 feet, seems to harbor the greatest quantity and variety of fungi. Prime time is from July through September, when the ground is alternately warmed by the morning sun and moistened by afternoon thunderstorms. A hard frost generally marks the end of the season.

“They grow basically anywhere where there’s enough moisture,” says Telluride poet and mushroom aficionado Art Goodtimes. “Go up to about 10,000 feet, and look in the fringe of the forests, where the trees meet the meadows,” says Good times, who has helped organized the Telluride Mushroom Festival for the past 20 years.

“It’s really a question of moisture,” he says. “You can go to an area one year and find plenty of mushrooms, and the next year, if there wasn’t enough rain, there won’t be a thing.”

To find mushrooms, you have to think like one, looking for moist, warm, and shady places. It’s possible to be standing in a field of mushrooms without knowing it. But once you see the first one, you start to get tuned in and begin to see the rest. Soon, you’ll learn to recognize the places they appear.

Is that a rotting tree stump under the moss pile? Look for delicate parasol-shaped fungi of the mycena genus.

And if you spot mushrooms on a live tree, you might find the poisonous red-and-white-spotted Amanita muscaria, commonly called the fly agaric.

Learning to love ’em

To some folks, mushrooms are the equivalent of slugs — slimy, low-life, good-for-nothing squishables. To others, however, nothing is quite so delectable as a slice of fresh forest fungus, sautéed in butter and garlic. After all, mushrooms have been considered a gourmet delicacy since Roman times, and some of the tasty varieties that grow right in our backyards are worth nearly their weight in gold at a high-class deli.

Identifying mushrooms requires a certain degree of patience and persistence.

The best way to learn is in the field with an experienced mycologist — especially if you plan to eat your find. It can require hours of hands-and-knees work, scrunched down over a clump of ‘shrooms with a guidebook and magnifying glass beside you. A big part of identifying fungi lies in understanding their habitat and that means studying them where they grow.

Of the thousands of species in Colorado’s high country, only a handful are desirable as edibles ,and another handful could be considered deadly poisonous.

Some of the edibles are easily recognizable, as are certain poisonous species. But the problem is, many more mushrooms, particularly the group informally known as the “Little Brown Mushrooms” (LBMs) fall in between. Of those, some are mildly poisonous, causing stomach upset in some people. Many others have not yet been identified either as edible or poisonous — perhaps because no one has tried them.

MUSHROOM POISONING is serious business. Several people get very ill from mushroom poisoning in the U.S. each year. On average, there have been 1½ mushroom-caused deaths annually in the past century, according to Shaw, who is the mushroom contact person for the Rocky Mountain Poison Center.

Shaw, who also served as the chair of the North American Mycological Society’s education committee, says the center fields about 450-500 mushroom-related calls per year, noting that not all of those are poisonings. Last year, for example, the center handled 38 cases of symptomatic poisoning.

“Keep one of every kind that you eat, unwashed, uncut and uncooked, in a brown paper bag in the refrigerator,” Shaw advises. A well-preserved specimen helps in identifying toxic species in potential cases of mushroom poisoning.

To distinguish the good from the bad, you need a basic course in mushroom physiology. Most decent guidebooks include a section describing and naming the different parts of mushrooms. All the experts say it’s important to develop at least a basic understanding of how they’re put together — it’s not enough to just try and match the pictures with the mushrooms you find in the woods.

The cap of the mushroom is pretty obvious — it’s the visible button we all know. The size, shape, color and texture of the caps all give valuable clues to a mushroom’s identity.

It gets a little more complicated at the stem, because some ‘shrooms have them and some don’t. That’s a clue in itself.

The structure, size and color of the spore-bearing surfaces, usually — but not always — on the underside of the cap, also provide valuable clues. Some mushrooms have gills, while others have a spongy looking mass of tubes. Spore-producing parts can take a wide variety of forms in addition to gills and tubes.

These are only a few of the many featured considered in making an identification. Some species can be distinguished by making a spore print, and examining the color and shape of the spores with a microscope. This involves placing a mushroom cap under a glass on a piece of paper for several hours until the spores drop. In many cases, the color is apparent immediately, and can help greatly in identifying a ‘shroom. In other cases, the flesh stains a certain color when handled, or when a chemical regent is applied.

Finding and feasting

It can be worth the trouble. Colorado’s mountains offer up a feast of wild edible mushrooms.

The majestic King Bolete (Boletus edulis), sometimes called “cep” or “porcini,” sometimes grows in great profusion in sub-alpine spruce and fir forests.

In German-speaking countries, this bolete is commonly called Steinpilz — literally translated as “rock mushroom” — probably because this delectable edible disguises itself as a lumpy rock, with a bulbous stem hiding beneath a lumpy, nondescript brown cap. These babies can grow as big as dinner plates, weighing in at several pounds each. Young ones are a little smaller — about 4 to 6 inches across the cap.

[The Boletus (Boletus edulis) is a delicious favorite for foragers.]

The single-celled threads grow together to form a mycelium — the subterranean bulk of the fungal organism. The cottony white mass is sometimes visible in damp forests on rotting stumps or among piles of wood chips. Some biologists now claim that the mycelium of some fungal communities may be the largest single living organism on the planet.

Another terrific edible that’s relatively easy to identify is the Chanterelle (Cantharellus cibarius), a vase-shaped ‘shroom that sporadically appears in great egg-colored clusters among the wood chips of decomposing conifers and under stands of old- and second-growth lodgepole. But be aware of several similar-looking species that are not so good, including the poisonous, glow-in-the dark Jack O’Lantern (Omphalatus olearius) and the False Chanterelle (Hygrophoropsis aurantiaca).

Goodtimes says one of his favorites is the strong-flavored Hawk’s Wing (Hydnum imbricatum), which he says he cooks into a kind of ragout. One guidebook (Vera Evenson’s Mushrooms of Colorado and the Southern Rocky Mountains) says only tender young Hawk’s Wings should be eaten, as the older ones make some people sick, and other mycophiles speculate there may even be several subspecies, of which some may not be as good.

Shaw says one of her favorites is the Shaggy Mane Inky Cap (Coprinus comatus), a widespread species that grows along roads and forest paths and other disturbed areas.

“It can be very common,” says Shaw, who likes to slice them thin and sauté them in just a little butter. The shaggy mane is one of a group of mushrooms whose caps turn into a sticky, inky black mass when they mature. Shaw says be sure to eat them before that process begins, and they’re not too appetizing in the later stages anyway.

Also delectable — but quite rare — are the morels, a unique looking mushroom that bears its pores on the outside surface of a pitted and ridged cap. Luscious Yellow Morels (Morchella esculenta) grow in groves of deciduous trees in riparian zones in the spring. Black morels (Morchella angusticeps) sometimes fruit later in the season among evergreens and aspens in the subalpine zone.

Morels sometimes thrive in recently burned areas and in orchards, but be aware of dangerously poisonous look-alikes, including the false morels of the Helvellaceae family. Gyromitra esculenta, sometimes called the Brain Mushroom or the Snowbank False Morel, has been touted as an edible, but Shaw and other experts warn against it, as it contains chemicals that produce relatives of hydrazine rocket fuel.

If you’ve managed to identify and bring home some edibles, you’re still advised to be cautious. Even edible varieties have caused allergic reactions in some individuals, so the experts recommend eating only a small amount — especially the first time you try a new variety — and only one kind at a time. In some people, mushrooms also seem to react badly with alcohol, so some guidebooks recommend against mixing alcohol and fungi. All the books recommend cooking all wild mushrooms before eating.

It’s also important to understand that some of the generalizations floating around are highly inaccurate. For example, one such myth has it that there aren’t any poisonous mushrooms in Colorado — well, there are. It’s also not true that insects and animals only eat edible species.

Other myths involve cooking mushrooms with a piece of silver or a coin (or a piece of garlic). Supposedly, if the mushroom doesn’t turn black, it’s OK. These are all myths, says Shaw, emphasizing that the only way to be sure is to make a positive ID of the species. Collectors should familiarize themselves with the poisonous species as well as with the edible ones they hope to collect.

A collecting ethic

Mushroom hunters, like others who use natural resources, must think in terms of resource conservation — the forest ecosystem depends on it. Vera Evenson’s book has an excellent section outlining an ethic for mushroom hunters, offered here in a condensed version.

[These fresh Chanterelles have a spicy apricot fragrance.]

Mushrooms are an important food source for many animals, and intensive collecting may disrupt normal feeding patterns. It’s also not clear if large-scale harvesting has any effect on fungal reproduction, and until there’s more reliable data, experts urge restraint.

Because of the mycorrhizal relationships between fungi and plants, indiscriminate picking could also have unknown long-term effects on the trees and shrubs. If the fungal life cycle is impeded by over-harvesting, trees might find it more difficult to extract nourishment from the soil. Weakened trees are more susceptible to disease and insect infestation, as well as fire.

IDENTIFY MUSHROOMS before you pick them. It’s easier to identify them when you study them in their natural habitat, anyway.

If you have identified edibles to pick, don’t pick all the mushrooms in any one area. In fact, leave two for every one you pick. Pick only mushrooms that are firm and mature, and leave some of the smaller buttons until they’ve had a chance to develop and drop some spores. Worm holes indicate the mushroom is past its eating prime, and is better left in place to reproduce.

Pry them away from the ground gently, trying not to tear the mycelium below. And don’t knock over every mushroom you see!

If every mushroom hunter develops a personal collecting ethic, it will help ensure that future generations will find the same amazing variety of fungus that we do today.

Bob Berwyn writes from Summit County, where he also collects and cooks wild mushrooms.