by Greg Marley
TAXONOMY
Honey mushrooms comprise a small group of closely related species of forest fungi. Not too long ago, most were lumped into Armillaria mellea, but taxonomists today generally recognize them as a complex made up of at least six species and perhaps up to fourteen, based on chemical, ecological, and morphological differences.6 In the Northeast, honey mushrooms growing on conifers are usually A. ostoyae and on hardwoods, either A. mellea or A. gallica. Most amateur mycologists or casual mushroom foragers will have a difficult time differentiating between these closely related species. To identify a honey mushroom, the best bet is first to determine whether the host tree is conifer or hardwood deciduous.
DESCRIPTION
(The following is a general description for all honey mushrooms and may not closely fit some varieties. The species in this complex are often difficult to distinguish using simple field characteristics alone. Consult a good field guide to your area for more detail.)
Honey mushrooms are tan to yellow-brown to brown mushrooms fruiting singularly or, more typically, in clusters on wood or on the ground from the buried wood of roots. (See #15 in the color insert.) The caps are generally 2–4 inches across and convex, becoming flat with maturity and with a region in the cap center with a number of dark, coarse hair-like scales. In the emerging button, the entire cap may appear covered with these scales. The gills are light tan, and attached to the stalk or slightly decurrent. The stalk is colored like the cap, generally twice as long as the cap is wide and may taper at the base. Each has a thick, fleshy whitish ring and often is irregularly scaly. The spore print is white.
LOOK-ALIKES
One mushrooming myth says there are no poisonous mushrooms that grow on wood and, therefore, any that you find on wood are safe to eat. Wrong! This myth, like many, contains a germ of truth. None of the polypore bracket fungi, which often fruit on wood, are poisonous. Although it’s more accurate, even this generality should never form the basis of a decision to eat a new mushroom. Never eat a mushroom unless you are 100 percent certain of the identification and the edibility of the species. When in doubt, throw it out!
There are several poisonous wood-rotting mushrooms with gills, none more notable and toxic than the deadly Galerina, Galerina autumnalis, and its cousins, which also grow singularly or in small clusters on wood. Unlike the honey mushrooms, it is smaller and produces a brown spore print. As its name implies, the deadly Galerina is a potentially deadly toxic species, containing the same cyclopeptide toxins that are found in death cap amanitas. Galerina mushrooms typically fruit in the same cool wet autumn weather that honey mushrooms favor.
Another famous and notable clustered wood-rotter is the jack o’lantern, Omphalotus olearius, which usually grows in dense clusters on the ground at the base of trees infected with its mycelium. (#8) Jack o’lanterns cause severe gastric upset in anyone mistaking them for edibles. A last potential problem mushroom is the brown-spored big laughing gym, Gymnopilus spectabilus, which grows on wood during the same autumn period and is generally quite bitter and also hallucinogenic.
A number of smaller mushrooms superficially resemble honey mushrooms but generally fruit singularly rather than in clusters. Be certain your collection contains the hallmark identification features of clustered growth, a white spore print, the presence of small dark scaly hairs on the cap, a thick fleshy ring, and attached or slightly decurrent gills.
ECOLOGY
The various species of honey mushrooms function as saprobes and parasites in the forest ecosystem. As saprobes, they are known as a “white rot” fungus because they consume the brown lignins in wood as a food source leaving only the white cellulose. In the process, they recycle the nutrients bound up in the wood. As parasites, honey mushrooms have earned a reputation as virulent pathogens, attacking, weakening, and killing a wide variety of tree species. Generations of foresters and land owners have regarded Armillaria root rot with a mixture of awe, fear, and loathing for the damage it causes to forest, orchard, and landscape plantings. As the mycelial network becomes established, it forms thick, dark-skinned rhizomorphs of densely compacted hyphae. These hyphae, which look like bootlaces or shoestrings, grow through the soil and search out the roots of new trees to invade, making the fungus capable of rapidly finding and attacking weakened trees over a broad area. The rhizomorphs, extending from an area of established infection, also act as effective conduits of moisture and nutrients to regions of an expanding mycelial network as the fungus moves into new territory.
An infected tree shows signs of distress within a year or two as the root function is compromised and the tree suffers from lack of nutrients and water, but sometimes trees can live relatively unaffected until they come under stress and the fungus overcomes the tree’s weakened natural defenses. On heavily infected trees or trees killed by Armillaria root rot, you can see a network pattern of the black bootlace rhizomorphs growing between bark and heartwood. The stump of a tree killed by root rot continues to house living mycelium for many years, serving as a site of inoculation for a new generation of trees planted in an area infected with honey mushrooms. For this reason, careful foresters mechanically remove infected stumps prior to replanting forests in areas where an aggressive honey mushroom infection has been active.7 Though honey mushrooms have a reputation as aggressive tree pathogens, some species live primarily as saprobes in the soil or become parasitic only when the trees are dying or under stress due to drought, insect infestation, logging, or other factors.
Another fascinating and eye-catching feature of honey mushrooms is occasionally seen by nocturnal visitors to the rain-moist summer forests. Wood colonized by honey mushroom mycelia occasionally exhibits bioluminescence, a faint ethereal light that glows in the dark to the fright or delight of unwary nighttime sojourners. (For more information, Chapter 16 on bioluminescence.)
EDIBILITY
The late Dr. Richard Homola, a former professor of mycology at the University of Maine, was an avid collector and photographer of Maine mushrooms and an enthusiastic fan of honey mushrooms. He told me that he preferred them to most other edibles and collected and preserved a supply of them for winter use. During the autumn months, usually after mid September in Maine, honey mushrooms will respond to a good period of rain by producing incredibly abundant flushes of fruit during a short intense period. This is a mushroom you can collect almost by the truckload in a good fruiting year. For the best eating, collect young firm caps before they become completely open. The tough stalks tend to be fibrous and are better left behind, although Tom Volk recommends peeling away the fibrous skin and eating the pithy inner flesh of the stalk. This seems a bit labor intensive for my style of cooking.
Honeys regularly fruit with abandon. Huge numbers will grow in clusters of young tight buttons interspersed with mature and over-mature individuals and the whole tableau can seem a bit overwhelming. It can also over-excite the greedy part of our psyche and lead to indiscriminant collection as we bring as many mushrooms home as we can carry. Once home and in the kitchen, make certain that as you prepare your collection for cooking or preservation, you again review each individual to be certain you have only honey mushrooms and that each is firm and healthy. Discard any questionable specimens or any that appear old or potentially spoiled. Many cases of mushroom sickening are due to the consumption of old mushrooms infected with bacteria.
CAVEATS
Whatever age or portion of the mushroom that you choose to eat, be certain that you fully cook your honey mushroom meal! Honey mushrooms contain a heat-labile toxin capable of causing mild to moderate gastrointestinal distress in unwary diners who value undercooked veggies. Dine on crisp broccoli or green beans and take a chance on rare beef, but feast only on well-cooked honeys!
I have a friend, a local chef of German descent, to whom I love to bring mushrooms. Following his friendly open smile at seeing the basket, he almost invariably will tell a story of his family’s use of mushrooms as survival food during the lean years in Germany follo
wing World War II. Unfortunately, he bought some honey mushrooms from a collector and, either not warned or unaware, lightly cooked them for his family. He awoke in the night to an uncontrollable urge to visit the bathroom and found it a popular room shared through the night with two other family members. All recovered before noon the next day, but learned the hard way to completely cook this species.
In addition to those stricken by undercooked meals, a very small percentage of people are unable to tolerate honey mushrooms and develop mild to moderate gastrointestinal distress after eating them regardless of the cooking. There are many theories regarding the cause of this phenomenon: mushrooms growing on conifers, over-indulgence, and allergic reactions to name a few. Because of this rare reaction, I recommend that the first time you eat honey mushrooms, try a small amount and see how it suits your system. I would not serve honey mushrooms to a crowd of mycologically naive diners without adequate warning. That said, I happily serve it in many forms to my family and generally dry a supply for off-season use in soups and stews where its robust flavor shines.
Walking through a forest picking the occasional cluster of tight young honey mushrooms, I rarely consider the mass of mycelia growing through the soil duff and colonizing the wood of the tree where the mushrooms have fruited. That this interconnected mat of fungal growth might cover several acres and have a combined mass that dwarfs me doesn’t intrude on my complacent collecting as I enjoy the fruits of all that labor. I certainly never consider building a boardwalk to exhibit the sight.
15
FAIRY RINGS AND FAIRY TALES
You demi-puppets that
by moonlight do the green sour ringlets make,
Whereof the ewe not bites . . .
SHAKESPEARE, The Tempest
And I serve the fairy queen,
To dew her orbs upon the green
SHAKESPEARE, A Midsummer Night’s Dream
I magine that you are a shepherd leading your flock of sheep and goats to good grazing ground on the high downs in southern England 350 years ago. In the fresh morning light, on the dew-covered downs, you come upon a sight new to your eyes and wondrous to your mind. A large sweeping circle of small mushrooms is fruiting along the outer edge of a grassy ring. The inside of the ring seems trampled; the grass is patchy and sparse with areas of almost bare ground. The rim of the circle, where the mushrooms peer above the grass blades, is just the opposite. Here the grass is growing more luxuriantly than in any of the surrounding area—tall, dense, and with a deeper green hue than the surrounding turf. You are certain that you have been past this spot before and have never seen this remarkable sight. It is as if some magic were at work. Could this be one of those fairy rings your grandfather has told you about? Quickly you gather the sheep into a tighter knot lest one stray into the circle seeking that rich grass. Your grandfather has told tales of the fate that awaits man or beast wandering onto such a fairy-blessed place.
There are certain experiences that serve to remind us all that there is an organizing force overseeing the universe, no matter what your religious affiliation. The thrill of coming upon a large fairy ring of mushrooms fruiting in the middle of a lawn or field is one of those moments for me. The almost unnaturally rich, tall, green grass surrounding a center of scrabbly grass and bare ground is equally thrilling. It’s no surprise that fairy rings have inspired awe, myth, and mystery throughout time and around the world.
Simply put, a fairy ring is a group of mushrooms sprouting together in an easily discernable circular pattern. The rings or arcs can range in size from a few inches to several hundred meters and are found all over the world in areas of temperate or subtropical climate. The largest known ring—located in France and created by the growth of the fungus Clitocybe geotropa—is more than a half mile in diameter and thought to be as much as 800 years old. It is common to see fairy rings that are 10–20 feet in diameter in lawns, ball fields, and parks.
The rings, or sweeping arcs of interrupted rings, are easiest to see on tended lawns or hay fields and are less obvious in pastures or in the woods. Fairy rings of mature mushrooms sometimes can be found in forests, especially when made up of larger fruiting species such as the fly amanita, giant puffballs, or white Clitocybe growing on smooth conifer needle duff. (See #16 in the color insert.)
Before scientists developed a good understanding of the fungus life cycle and growth patterns, many explanations—mundane, fantastical, and supernatural—were put forth in an effort to explain the strange and striking presence of fairy rings in our midst. Here are some of the better known beliefs associated with fairy rings around the world.
In a number of regions in England and continental Europe, it’s said that fairy rings appear in places where the fairy folk meet, hold their balls, and dance. The mushrooms that appear around the edge of the rings are resting seats for the tired fairies. In Sussex, England, fairy rings were called hag tracks, while in Devon it was believed that fairies would catch young horses in the night and ride them round in circles. Also in England, it was long thought that the dew on the lush grass at the edge of the fairy ring was collected by country lasses and purported to improve the complexion, or used as the base of a love potion. In Denmark, elves traditionally have been blamed for the rings and in Sweden, a person entering a fairy ring passes entirely under the control of the fairies. The Germans and Austrians believed the bare patch in the center of the ring is where a fire dragon rested after his nightly wanderings. In many regions, it was thought that fairy rings marked the location of treasure, which could not be secured without the help of the fairies.1,2,3,4
And here in the United States, The Monadnock-Ledger of Jaffrey, New Hampshire, supposedly reported a large fairy ring found during the summer of 1965 and attributed its presence to having been left behind by a flying saucer. That same summer, sightings of UFOs were reported from the nearby the town of Exeter, New Hampshire.
Natural phenomena also have been used to explain fairy ring formation. Over time, people have attributed them to ants, termites, and moles, cow or horse urine, the result of haystack placement, and the action of thunder and lightning. In 1791, Erasmus Darwin in his epic poem The Botanic Garden postulated that the causal agent was “cylindrical lightning” that burned the grass in a circular pattern and was responsible for the resulting increase in soil fertility. Darwin wrote: “So from dark clouds the playful lightning springs, Rives the firm Oak or prints the Fairy Rings.”5
We now know that fairy rings result from the unrestrained growth of fungal mycelium through its grassy growing medium and the equally unrestrained fruiting of the fungus along the outer rim of the ring of growth. Consider a pair of spores of a mushroom such as the meadow mushroom, Agaricus campestris, or fairy ring mushroom, Marasmius oreades, germinating in an open grassy field. These mushrooms are saprobes that feed off the dead grass blades and roots in the top layers of the soil. Once the spores germinate, the hyphae begin to grow outward and, in the absence of any breaks in the continuity of the food source and moisture, the network of hyphae will grow and feed its way through the grass duff at an equal rate in all directions.
Once established, the rate of fairy ring growth can average 5 to 9 inches per year depending on the consistency and amount of rainfall. If the fungus produces mushrooms the first year, it likely would be a small cluster at the point of origin, and any increased growth of the grass could be easily passed off as a result of animal defecation in the absence of fruiting mushrooms.
As the mycelium grows outward, the area of maximal feeding moves outward as the mycelium encounters new organic matter, and the interior portion of the expanding circle becomes depleted of nutrients. The soil in the center of the ring is therefore less fertile and the grass there looks stunted with bare patches of ground. (This retarded grass growth also has been attributed to the mat of mycelium blocking the uptake of water into the soil.) Along the leading edge of the ring, the fungus is actively “feeding”—breaking down the dead plant matter into basic nutrient
s. With more available nutrients, the grass grows more luxuriantly than either the grass inside or beyond the growth of the fairy ring. It is unusual for a patch of ground to be perfectly homogeneous and free of obstacles; therefore it’s unusual to see a fairy ring of any size that isn’t interrupted in some way. Most grow out as one-sided arcs or curved lines and others become misshapen as one area grows at a different rate than another due to variations in soil moisture, food availability, rocks, ledges, or other factors.
Mushrooms Commonly Found in Fairy Rings
As a mycophile always in pursuit of good edibles to grace my table, I seek out fairy rings as both a curiosity and a potential source of food. Although I know that some mushrooms growing in fairy rings are toxic, many are edible, so I keep an eye out for the lush grass growth in summer and fall that tells me I might find some mushrooms when they’re fruiting.
When I look through the literature and on the Internet for information about fairy rings, I’m somewhat surprised and amused at the number of references to them as a disease of lawn and landscape. There are how-to Web sites devoted to ridding well-tended lawns of this troublesome scourge. (I am constantly amazed at the lengths some people will go to in pursuit of the perfect-looking lawn.) The remedy generally involves intensive aeration, application of herbicides (often not effective), extra nitrogenous fertilizer to mask both the bare spots and the lush growth and, if all else fails, the removal and replacement of the topsoil in an “infected” area. Seems like a whole lot of work to kill off a fascinating backyard exhibition of fungal growth and a source of potentially edible mushrooms. Besides, if we rid ourselves of the fairy rings, where will the poor fairies dance?
