by Greg Marley
ECOLOGY, HABITAT, AND OCCURRENCE
Both false and true morels appear in the spring as the weather is warming. Occasionally, young false morels emerge along the receding edges of snow banks or shortly after lingering drifts melt. This is more common with the related G. gigas, called the snowbank false morel in the mountainous West where it is common. The false morels in New England generally appear around the same time as the early black morels, Morchella elata, and overlap with the initial flushes of the yellow morels, Morchella esculenta. I have found the false morel and yellow morels in the same area on the same day. In a region as geographically diverse and large as New England, there is considerable variation in fruiting times of both groups from south to north and as elevation increases. The most delayed appearance would be in the northern and western mountains where many emerging plants and fungi appear two to three weeks later than in southern locations. In the mountains of the western United States, sponge mushrooms fruit commonly throughout June at higher elevations.
The most common species of false morel in New England, G. esculenta, is often found in association with white pines. Long considered a saprobic organism, living off the decomposition of dead plant material, these false morels are now seen to have the ability to form mycorrhizal relationships with trees during at least a part of their life cycle.2 This helps explain why they can often be found in the same location in successive years.
TOXICITY AND/OR EDIBILITY
False morels have been described as edible mushroom that sometimes kill.3 They also have been called deadly poisonous mushrooms that are considered desirable edibles in Europe and parts of North America. John Trestrail, retired chairman of the Toxicology Committee of the North American Mycological Association (NAMA) and managing director of Spectrum Health Regional Poison Centre in Grand Rapids, Michigan, summed up the danger very nicely, “Persons who decide to continue this gastronomic gamble should have the number of their regional poison centers engraved on their eating utensils.”4
The compound gyromitrin, the main toxic component in this species, was not isolated until the late 1960s and much of our understanding of its mode of action on the body and its physical characteristics come from the U.S. military. Why the military? Gyromitrin quickly converts to monomethylhydrazine (MMH) in the human gut, and MMH has been used as a fuel for rockets in this country and around the world, and we all know who uses rockets. The toxic and carcinogenic nature of the MMH prompted the military to seek a better understanding of how to handle the chemical safely and to care for workers exposed to MMH. A highly volatile liquid, MMH has a boiling point of less than 90 degrees Centigrade. It continues to be just as toxic in the vaporous state, making even the process of boiling off the toxin a risky act if done in a poorly ventilated space. In Europe there have been cases where people who dry commercial quantities of the mushroom have been poisoned by the fumes given off in the drying process. The suggested method to prepare false morels safely for food involves repeated cycles of parboiling. One must be certain to boil them in a well-ventilated space and to discard the water used in the boiling, because it also contains toxic quantities of MMH. The volatile, airborne MMH is able to enter the body through unbroken skin!
The Enigma of Gyromitrin Poisoning Cases
As I address in the section on mushroom poisoning, there is a significant idiosyncratic element to mushroom interactions in the human body. A group of people eating the same quantity of the same toxic mushroom will likely react in different ways. One person might become very sick, several mildly ill, and others will not be affected at all. With false morels, the challenge of predicting the circumstances under which a person will become sick after eating this mushroom is much more difficult and even less understood.
The difficulty seems due to a number of possibly interacting factors. The concentration of the toxin gyromitrin varies greatly in samples of false morels and seems affected by the specific strain of mushrooms, the age or maturity when they were picked, and how warm or cold the days have been. There have long been assertions that mushrooms collected in different countries or between in and North America might vary in toxin concentrations. This has been used, at times, to justify the ongoing use of false morels as food. I have seen no studies attempting to assay and quantify any such variation, if it exists. Specimens grown at high elevations have lower concentrations of toxins than those at lower elevations in at least one study.5 This seems to be contradicted by another study from Finland showing that strains grown in warmer temperatures have lower levels of toxins than those grown at cooler temperatures. It would make some sense that, in warmer, sunnier conditions, a volatile toxin might be evaporated out of the mushroom. If the ultraviolet radiation from the Sun is responsible for volatilizing or neutralizing the toxin, higher elevations might result in lower toxin concentrations because of increased UV radiation in the thinner atmosphere at high elevations.
Studies on the toxicity of MMH using monkeys have shown that there is a very narrow margin between a dose causing no observable symptoms and a lethal dose. In humans (unwilling to undergo the same experiment to which we subject the monkeys), this also appears to be true though no studies have been attempted.6
There appear to be great differences in individual sensitivity to gyromitrin. This may explain why there is such marked difference in the response of individuals in a group after eating this mushroom. Some will be without symptoms, others will become very ill, and still others may die after the same meal. Most of these observations have been based on uncontrolled settings without the clear knowledge of amounts eaten. It does seem more certain that there is a dose-related threshold after which someone will become ill. People are more likely to become ill if they have eaten several meals of false morels over a short period of time. It is not clear whether this is related to a developing sensitivity to the toxin or if there is a cumulative dose at work.7 The mushroom poisoning literature throughout the past century contains numerous accounts of people who ate false morels without any problems for many years only to become very ill after another meal of the species. Drying fresh mushrooms removes much of the toxin, but not all. Boiling the fresh mushrooms twice for ten minutes in a significant volume of water removes almost all of the toxin. Of course, given the toxic nature of vaporous MMH, this must be done in a very well ventilated room.
The history of gyromitrin poisoning has shown us that rarely is there a mild case. The threshold toxic dose of gyromitrin is only slightly higher than a dose producing no symptoms of illness, and many who become ill have serious symptoms that can include liver damage. Poisoning from gyromitrin-containing mushrooms can kill! A literature review of cases occurring between 1782 and 1965 showed a mortality rate of 14 percent in Europe.8 According to NAMA’s thirty-year review of mushroom poisoning cases, there were twenty-seven cases of poisoning by Gyromitra esculenta during the period ending December 2005.9 In nine cases (33 percent) there was liver damage reported, and in three cases (11 percent), kidney damage. Michael Beug found no reports of deaths caused by gyromitra in North America over the thirty years, although anecdotal reports of earlier deaths in this country abound.
Symptoms of Gyromitrin Poisoning
In a pattern following the majority of potentially deadly mushrooms, the time between eating false morels and the onset of symptoms is typically delayed. Symptoms do not generally start for six to twelve hours, though in cases of severe poisoning they may start sooner (a bad sign). In cases of mild poisoning the symptoms last from two to six days, although those with kidney of liver damage can have ongoing chronic problems. The initial symptoms affect the gastrointestinal tract and include bloating, gas, nausea, and accompanying vomiting and cramps. Severe headache and fever also may be present in the early phase. After thirty-six hours, more severely poisoned victims can develop signs of liver failure including jaundice and swelling of the liver and spleen. The breakdown of red blood cells and corresponding increase in plasma proteins can overwhelm the kidneys at a time they are respondin
g directly to the toxins, a combination of factors that has led to renal failure in some people. Those individuals ingesting a lethal amount of gyromitrin then enter a neurologic phase with potential convulsions, delirium, coma, and death.10
The Controversy of the Poisonous Edible Mushroom
Reconciling the former reputation of the false morel as a great edible mushroom and its newfound status as a potentially deadly species has not come easily or clearly in the mycological community. There can be little doubt why the general public would also be confused. I have reviewed numerous popular mushroom field guides written by a number of leading mycological authorities over the past 100 years regarding the edibility or poisonous nature of the false morel. They illustrate the split personality of this mushroom in the eyes of both the amateur and professional mushrooming world and the slow development of consensus regarding the risks posed by eating most species of false morels.
Charles McIlvaine was a passionate American mycologist at the beginning of the twentieth century, famous for his eager experimentation with, and comments on, the edibility of many mushroom species not normally consumed in this country. In his 1902 One Thousand American Fungi, he gives his input regarding the edibility of false morels, “Since 1882 friends and myself have repeatedly eaten it. In no instance was the slightest discomfort felt from it. It was always enjoyed.” McIlvaine goes on to state, “but the species, though long ago esteemed highly in Europe and by many in America, now rests under a decided suspicion. It is not probable that in our great food-giving country anyone will be narrowed to G. esculenta for a meal. Until such an emergency arrives, the species would be better left alone.”11 McIlvaine penned these words without further information regarding the problems associated with eating the false morel—a case of being praised with faint damnation.
Writing some thirty years later in The Mushroom Handbook, Louis Krieger was equally ambivalent about the edibility of the false morel. “It is known to be deadly poisonous, yet many people, both here and abroad, consume it without the slightest trace of serious consequences. Against this stands the plant’s record as the slayer of one hundred and sixty people. It would seem that either we are dealing with two distinct forms of a species, one edible, the other deadly, or such consumers as survive are possessed of a natural insensitivity to the poison.”12 Again, there is no clear statement about whether or not it is safe to eat.
In the early 1940s, Clyde Christensen seemed almost apologetic when he condemned the false morel to his blacklist in Common Edible Mushrooms. He praised it as an edible and then stated, “The fact remains that in both Europe and America it has been known with certainty to cause fatal poisoning. Many of these cases have been too well authenticated to permit reasonable doubt as to the identity of the fungus responsible. Such cases are rare, to be sure, and most of them have occurred among people who were sick or undernourished.” In the end, the extent of the reported problems outweighed his regard. “Considering the extent to which the fungus is eaten and the general excellence of its reputation, it is with some misgiving that the author puts it on his blacklist, but the fact that it has been known, unquestionably, to poison people is sufficient justification for condemning it.”13
In 1951, Canadian mycologist Rene Pomerleau took a clearer approach to the conflicting reality between safe edible and toxic killer by stating the steps to take to render the species edible. “In spite of its name, several authors claim that the Edible Gyromitra is not always safe and may sometimes cause serious troubles. Many individuals (the author himself) can eat this mushroom without harm. Its toxic component is eliminated when parboiled. However, one should try only a small amount for the first time.”14 This mixed message seems balanced to discourage the cautious soul and encourage dangerous behavior in a risk-taker.
In 1977, Orson Miller published his well-received Mushrooms of North America in which he divided out several species of false morels and classified G. esculenta as an edible western United States species. He reported that a closely related eastern American species was problematic and emphasized that he would eat only specimens collected in the Rocky Mountains or Pacific Northwest.15 We now recognize the eastern species as G. esculenta. In publishing The Audubon Field Guide to North American Mushrooms only four years later, Gary Lincoff extended the cautionary note on all G. esculenta across the country while acknowledging that most reports of poisoning occur east of the Rocky Mountains. Both Lincoff and West Coast author David Arora, in his 1986 edition of Mushrooms Demystified, identify the toxins in Gyromitra as a derivative of monomethylhydrazine, the toxic and carcinogenic compound also found in some rocket fuels.16 Knowing the identity of the toxin, they also wrote more authoritatively regarding the use of drying, parboiling, and cooking as historic methods for drawing off the volatile compounds and rendering the mushroom safer for consumption. They also carefully caution the reader to avoid eating the mushrooms.
In 1995, Dennis Benjamin, a pathologist and dedicated mushroom toxicological expert, published the book Mushrooms: Poisons and Panaceas, which has become an invaluable resource for all interested in mushroom poisoning. I greatly respect the line Benjamin has taken in his treatment of the false morel and his acknowledgment of the reality that, as toxic as the mushroom has proven to be in many cases, it continues to be consumed by many, many people, especially in the western United States, where he lives. (One estimate by John Trestrail indicated that over 1 million worldwide and up to 100,000 people in the United States eat false morels.17) Benjamin includes complete and accurate information regarding the toxins, the species known or suspected of causing poisonings, and a picture of the clinical course of the poisoning. In addition he explores recommended treatment and supportive measures for poisoning victims under medical care. Now here is where he tips his hat to the elephant in the room. He gives clear recommendations to avoid these toxic mushrooms and also includes a set of guidelines for the safe preparation of false morels for consumption.18 I find myself caught between viewing this as a dangerous mixed message and a very thoughtful example of informed consent.
The Finnish Fugu
There is no other region of the world like Finland, where false morels are treasured for consumption and sold fresh, dried, and even commercially canned. Marianna Paavankallio is the author of the Web site Marianna’s Nordic Territory, which features information on Finnish edible and poisonous mushrooms, as well as many mushroom recipes. According to Paavankallio, of the seventeen deaths in Finland attributed to mushroom poisoning between 1885 and 1988, only four were caused by korvasieni, as the false morel is known in Finland (although it’s worth pointing out that four translates to almost 25 percent of the country’s mushroom poisoning deaths). “Mushroom experts from outside Scandinavia are frequently shocked to discover that the deadly toxic false morel (Gyromitra esculenta) is regarded as a delicacy in the Nordic countries, where it is sold commercially and regularly consumed. Often they seem to think that their Nordic colleagues must be totally ignorant of false morel’s toxicity. The truth is, however, that every single man, woman and child who was born in Scandinavia knows—at least in Finland—that the false morel is lethally toxic if eaten raw and that even inhaling its fumes can cause poisoning symptoms.”19
The Finnish Food Safety Authority, Evira, recently published a brochure about the safe preparation of korvasieni and requires the information to be included in the packaging of any false morels sold fresh or dried in the country. It is available in many languages in part because the Food Authority believes that natives know of the risks, but that foreign visitors might either believe that the mushroom is deadly poisonous or don’t know it is edible and most certainly need accurate information on ridding the mushroom of the toxin.20 The care needed in rendering the false morel into a safe edible has led a few to dub the mushroom the Finnish fugu, in honor of the prized Japanese puffer fish of the same name and similar toxic nature. I am one American not inclined to eat false morels and caution the reader to avoid this form of mushroom Russian rou
lette.
10
A FALLEN ANGEL
Out mushroom hunting—
dangerously close to caught in
late autumn showers
MATSUO BASHO (1644–1694)
September 2004 followed an unusually wet and warm summer in Japan. The Sea of Japan was in the path of an unusually large number of named typhoons that had come ashore in parts of the country that year and, as in all wet years, the beach-goers complained and the mushroom gatherers rejoiced. Mushroomers took to the forests and fields, and a variety of fungi were gathered and eaten with great enthusiasm by the locals throughout this highly mycophilic land. Along with many parts of China and Korea, Japan is one of the more mycophilic regions in Asia.
The first recognized victim sought help in mid-September. An elderly woman was brought in to a local hospital exhibiting slurred speech, unsteadiness of gait and balance, light-headedness, and an overall sense of malaise. Over the next days, her symptoms progressed to tremors in the extremities, seizures, and increasing disturbance in consciousness as she slipped toward coma, finally requiring intubation and ventilation. The patient died of symptoms associated with acute encephalopathy fourteen days following her admission to the hospital. Simply put, encephalopathy (literally brain death) is a deterioration or degeneration of the brain tissue.
There were more than fifty other victims spanning six Japanese prefectures that fall. Over the course of two months, at least fifteen deaths across the country were attributed to this outbreak of encephalopathy. Autopsies showed brain lesions, specifically in regions of the brain known as the basal ganglia and the insula.1 The victims shared many things in common beyond their illness. Many lived in the prefectures of Yamagata, Akita, and Niigata along the northeast coast, almost all were elderly (the average age was sixty-nine), and each person had a history of moderate to severe kidney dysfunction, including many who had a history of kidney dialysis. The final unifying characteristic was that they all also had eaten one type of common wild mushroom within a month prior to the onset of their symptoms. In many cases, they had eaten the mushrooms as part of several meals in the weeks prior to the outbreak of their symptoms. Many reported a long history of collecting and enjoying the mushroom in question.
