by Greg Marley
The situation above is a typical example of mistaken identity and there are several ways to avoid repeating it. First, know the characteristics of the most dangerous and most common toxic species in your area and avoid eating mushrooms with close toxic look-alikes. The classic example is the genus Amanita, the group of mushrooms responsible for the majority of serious poisonings and deaths in temperate climates. All members of this genus have a set of common features—free gills that give off white spores, a swollen stem base with remnants of a universal veil, and the presence of an annulus, or ring, around the mid-stem—that are apparent even to the untrained eye. It is the responsibility of anyone who wants to eat wild mushrooms to be familiar with the amanitas and their shared identification features. When these features are found together, it should place a mushroomer on high alert. The genus Amanita has some very edible and desired mushrooms in addition to the toxic species, but I strongly discourage novice collectors from eating from this group. In addition to amanitas, the genera Lepiota and Macrolepiota share many characteristics with amanitas, including the presence of some severely toxic species (as well as some great edibles). It is another genus to be avoided by all but the most experienced mushroomers.
Most good mushroom field guides include cautions about toxic look-alikes in their descriptions of edible mushrooms. Some guides, such as the Audubon Field Guide to North American Mushrooms, are particularly good at this. Again, my mantra about eating mushrooms that have toxic look-alikes or are known to cause problems for some diners is, “Why bother?” Why bother taking a chance when there are so many great, easily identifiable edibles growing in our forests, fields, gardens, and lawns? Start out with a couple of the common “Foolproof Four” and add to them as you become more competent at identification.
The Mycological Immigrant: Strangers (Eating Mushrooms) in a
Strange Land
The mushroom poisoning literature is filled with stories of recent immigrants who collect and eat mushrooms found in their new homeland and who base their identification on knowledge and collection history from another region of the world. The most tragic cases in the United States have often involved Asian immigrants collecting and eating deadly toxic death caps, Amanita phalloides, believing they are edible paddy straw mushrooms, Volvariella speciosa. The result has been several deaths and serious illnesses that required life-saving emergency liver transplants (see Chapter 8).
Situations that result in less severe outcomes are far more common. A few years ago I handled a mushroom identification call from our regional Poison Control Center that involved two Central European sisters and one sister’s American husband. The sisters, who had recently moved to the United States from Germany, had a long history of collecting and eating mushrooms as a normal part of their diet. It was late summer, there had been a prolonged period of rain, and the boletes were fruiting.
The sisters collected and cooked a meal of boletes and all three partook, though the sisters ate fewer mushrooms than the man did. After the meal, the man suffered from nausea and vomiting for about five hours before going to the hospital and, while there, reported that his wife and her sister also felt ill but had not developed his severe symptoms. Based on descriptions and photographs, it was determined that the mushrooms eaten were the lilac-brown bolete, Tylopilus eximius. The man was kept overnight, treated with IV fluids and something to control his nausea, and released the following day.
According to the patient and the emergency department doctor, the man’s wife said she collected and ate a similar species in her native country. However, the lilac-brown bolete, which has been responsible for a number of cases of illness in New England and eastern Canada, does not occur in Central Europe. Many Europeans grow up learning that almost all boletes are edible with the exception of some of the red-pored, blue-staining species. Clearly, and unfortunately, the toxic nature of T. eximius in Maine was new to this recent immigrant.
Moving into a new area—especially if it involves a radical change in climate—challenges the mushroomer to learn new species and the ecological associations related to their growth. If the climates are similar, they will likely be home to many of the same major species. Many of the more common and popular edible mushrooms hunted for food in Europe, such as the golden chanterelle and the king bolete, are also common or have similar, related edible counterparts in the United States.
Like all strangers in a strange land, the immigrant mushroomer, whether moving from Michigan to Florida or Vietnam to Northern California, needs to learn the local mushrooms before eating them. The best option is to find an experienced guide in the new location. Others might get by with the purchase and use of a mushroom field guide covering the new region. As with many aspects of life, the danger is in assuming that nothing is different.
The Adventurer
Adventurers are characterized by a lack of rational concern about the identity of the mushrooms they eat. Another way of looking at it is that they share an affinity for dinner by mushroom Russian roulette. In my experience, they have included a sixty-year-old man who collected and ate the pretty white mushrooms growing near his compost pile and later reported to the doctor covering his case of gastrointestinal distress that the mushrooms looked “beautiful and benign.” He cooked and ate them, making no effort to identify his dinner. Fortunately for him, those pretty white mushrooms were not the pure white destroying angel, and he recovered.
I’ve also seen a man in his mid-twenties who, while walking in the woods with a friend, found an unusually large cluster of robust brown mushrooms fruiting on a stump. He reported to me that he’d eaten raw mushrooms in the woods before without any difficulty and felt he had a good sense of what would be edible. Both he and his friend reportedly ate one or two caps of the mushrooms raw and, while his friend became quite ill within two hours and had violent gut-cleansing symptoms for about twelve hours, the other young man—the one I questioned—did not develop symptoms for about twenty-four hours, but reported ongoing difficulty holding down food for the next ten days with only a slow abatement of the distress. He said that eating the mushroom was an impulsive act; he’d had no intention of collecting mushrooms and has had no training in mushroom identification. He also assured me he did not collect the mushrooms to get high.
Adventurers tend to be people with a sense of invincibility, magical thinking, and a dearth of common sense and judgment. Fortunately for them, less than 10 percent of the species of mushrooms they are likely to find are toxic and only a few of those possess toxins capable of severe damage or death. “God protects fools, drunks, and little children.” Based on the literature of mushroom poisoning and the rarity of lethal events, this also seems to hold true for adventurers.
There is another sort of adventurer—those who seek mushrooms for the experience of hallucinations, visions and mind expansion, or the recreational high. Many adults have made rational, educated decisions regarding use of psychedelic mushrooms. They’ve done their homework to correctly identify the mushrooms they seek, as well as identify the risks involved, and many have had positive experiences, which, for some, have been life altering.10 Paul Stamets in his 1996 revision of Psilocybin Mushrooms of the World gives a series of suggestions for the responsible and respectful use of hallucinogenic mushrooms.11 Unfortunately, some young people using these mushrooms are seeking the high without the homework. When they are out collecting their own mushrooms, this can mean confusing toxic little brown mushrooms (LBMs) for the psychotropic ones. Some LBMs contain dangerous levels of muscarine. A few, found growing in the same habitat as certain psilocybin mushrooms, contain the deadly amatoxins.
Treatment challenges can arise from people who collect and eat mushrooms but are unsure of their identification skills, or worse still, are not aware of how little they know until too late. The anxiety that sets in once the mushroom has been eaten is often enough to produce symptoms of panic in the anxious neophyte.
It was an early autumn evening in 2006 when I received the call
regarding a twenty-something male who had ventured into the woods in search of the big laughing gym, Gymnopilus spectabilis. The laughing mushroom and a couple of related species contain hallucinogenic psilocybin and psilocin, though they are not well known or recognized as psychedelic mushrooms in the Northeast. The young adventurer, who apparently had read about the laughing mushroom online, collected a number of mushrooms and ate some of them before returning home. It was only when doubts about accurate identification began to settle into his consciousness that he, again, looked up the description, became increasingly unsure that he’d eaten the correct mushroom, and began to feel flushed, nauseous, and panicky. He arrived at the hospital emergency department in full panic and, following contact with the regional Poison Control Center, I was contacted to provide identification expertise. The digital images of the mushrooms collected and consumed proved to be a mixture of four different species, none of which were the laughing mushroom. Fortunately, none of the species presumably eaten were dangerously toxic either. The symptoms shown by the “victim” in this case could all be explained by his rising sense of panic over eating mushrooms he did not know compounded by his fear that they might be dangerously toxic.
Mushrooming is a great hobby and a healthy way to get out into nature. Eating mushrooms adds a richness and variety to the diet and focuses your mushroom education. For a careful person, the risk of eating a bad mushroom is very low and easily avoided by following my guidelines.
* Muscongus is a bay on the coast of Maine.
8
AMANITA NIGHTMARES
The Death Cap and Destroying Angel
Among all those things that are eaten with danger, I take the mushrooms may justly be ranged in the first and principle place; true it is that they have a most pleasant and delicate taste, but discredited much they are and brought to an ill name, by occasion of the poison which Agrippina the empress conveyed unto her husband Tiberius Claudius, the Emperor, by their means a dangerous precedent given for the like practice afterwards. And verily by that fact of hers, she set on foot another poison, to the mischief of the whole world and her own bane especially (even her own sonne Nero, the Emperor, that wicked monster).
PLINY IN THE NATURAL HISTORY OF THE WORLD, A.D. 23–79
Pliny’s description of the alleged murder of Emperor Claudius in the first century A.D. is perhaps the oldest surviving record of a mushroom being used as an instrument of murder and regime change. While the cause of Claudius’ death is a matter of historical debate, according to this version of the story, the Emperor’s fourth wife (and niece), the Empress Agrippina, plotted to elevate Nero—her son from a previous marriage—to the throne. She first convinced Claudius to adopt Nero, putting Nero in line for ascension, and then laced the emperor’s dinner plate with either the juice or chopped fruit of the death cap, Amanita phalloides. Claudius, who was a well-known glutton and inordinately fond of mushrooms, thought he was eating the colorful and tasty Caesar’s mushroom, Amanita caesarea, a mushroom of high acclaim across Europe, prized by nobility of the Roman Empire, and one of his personal favorites.
According to the historian Tacitus (circa A.D. 55–117), the emperor finished his dinner and enjoyed the evening without ill effect, but got sick during the night and stayed sick for some extended time thereafter. He enjoyed a brief recovery after emptying his system, but in Tacitus’ next entry, the doctor Xenophon was called to attend to the needs of the emperor and tried to make him vomit by sticking a feather down his throat. This seems to indicate that Claudius again became ill after his initial recovery, a course of illness consistent with amatoxin poisoning. Some historians suggest that Xenophon was part of Agrippina’s plot and administered a second poison to the victim at this point, perhaps an enema of colocynth, a powerful purgative. Whatever the case, Claudius’ condition deteriorated, and after a significant delay, the death of the Emperor Claudius was announced and Nero assumed the throne.1 Once, again, the delay before death is consistent with amatoxin poisoning taking a number of days to kill a victim.
Sad to say, the story may be true and such tales are what give mushrooms a bad name. If the goal has been to vilify mushrooms, the choice of Amanita phalloides as the poster child of mycological villainy would be ideal. The death cap, which has long been upheld as the most dangerous and deadly of mushrooms, is responsible for the majority of serious poisonings and deaths by mushrooms across the world. In Europe, it accounts for an estimated 80–90 percent of mushroom-related deaths.2 In the United States, serious poisonings by Amanita mushrooms have mostly involved the death cap and the closely related destroying angels, A. bisporigera, A. virosa, and A. ocreata. (See #12 in the color insert.)
The Amanitas
The death cap is a medium-large, beautiful mushroom with greenish-beige cap commonly found in forested regions across much of Europe and Asia. Though not native to North America, it was introduced to this country in the last century, most likely as an inadvertent mycorrhizal hitchhiker on the rootstock of imported trees, especially European oaks, pines, and spruce. In the United States, it has become naturalized and common in the West Coast states of Washington, Oregon, and Central and Northern California. The death cap is also found increasingly in the Midwest, Mid-Atlantic states, and southern New England. The mushroom was recently collected in Maine for the first time. Though it seems to prefer growing with species of trees in the oak family, it also is found with species of pine, spruce, birch, hornbeam, and horse chestnut, and reportedly now with hemlock. Rod Tulloss, one of the leading authorities on the genus Amanita in North America, reports that, in the western hemisphere, the death cap has been introduced into locations from Canada to Argentina, and, therefore, few forested regions should assume they are safe from this deadly mushroom species. Once established in an area on introduced trees, it can naturalize onto native trees and shrubs, a behavior that’s been noted extensively on the West Coast. Such migration of an introduced mycorrhizal fungus onto native plant species is being increasingly referred to as mycorrhizal invasion. So far, in the Northeast the death cap has been more restricted, and has rarely spread from plantation sites where it’s been initially established.3
The death cap is so dangerous, in part, because it resembles several edible members of Amanita, as well as edible species of the genus Volvariella. The paddy straw mushroom, Volvariella volvacea, is a popular edible mushroom of the tropics, especially in Asia, where it is widely cultivated on rice straw. It is frequently used in Asian cooking and is widely available canned in the United States. A second species, the common volvariella, Volvariella speciosa, is an edible mushroom regularly found in gardens and fields. Both of these species share the characteristic distinctive volva of the amanita, a cup of tissue surrounding the base of the stem that is the remnants of the universal veil, a sac fully enclosing the young mushroom in the button stage. Because the edible volvariellas are normally collected and consumed in the firm button stage, enclosed within or barely out of the universal sac, they look a great deal like young amanitas in the button stage. Several families who have mistakenly eaten the death cap have been recent Asian immigrants to the United States and naïve about the wild mushrooms in their adopted country, believing they were collecting edible mushrooms. This scenario—of new immigrants collecting and eating mushrooms resembling a known edible back home—is one of the most common situations in which deadly amanitas are eaten in America. A significant proportion of amatoxin poisonings in America in recent years involve newly arrived or first-generation immigrants.
As with many groups of mushrooms, the taxonomy of the genus Amanita is complex and the understanding of the relationships among species is in flux. Many current mushroom guides refer to the North American species of destroying angels as Amanita virosa or A. verna. Recent taxonomic studies suggest that both of these names refer to European species and that the majority of pure white Amanita species in our northeastern woods belong to the species Amanita bisporigera.4 The genus Amanita is quite large worldwide, encompas
sing more than 500 “named species” according to Amanita expert Rod Tulloss, and mycologists generally agree that the North American amanitas are not well understood. I recall a conversation with Tulloss at the 2007 Northeast Mycological Federation Foray in Orono, Maine, in which he recalled his state of mind at the onset of his Amanita studies. He said that, at the time, he felt that it would be a good project of relatively short duration. Now, many years later, he regularly comes across specimens that don’t correspond with any known species and admits that a revision of the group is nowhere near completion.
The Toxins: Amatoxins
Amatoxins, the liver-destroying toxins found in amanitas, are so potent that it takes as little as 0.1 milligram (mg) of alpha-amanitin per kilogram of body weight to kill a person. A lethal dose for the average-sized adult is only 6–7 mg. Analyses of mushrooms show that Amanita phalloides caps contain between 0.5 and 1.5 mg of alpha-amanitin per gram of tissue, with the greatest concentration in the gills of the mushroom. Since the cap of A. phalloides can easily weigh 50–60 grams, a cap that is four inches in diameter could contain enough toxin to kill several people!5 The cap of a destroying angel, Amanita bisporigera, contains, on average, about half the concentration of alpha-amanitin as a death cap, which makes it less potent, though still capable of causing death. Concentrations of the toxins can vary according to the age of the mushrooms, between mushrooms found in different locales, and even between individual mushrooms growing together in the same locale.
