A key to the main mushroom genera covered in this book that have various shapes—those not cap-shaped with stalks.
mushrooms that grow on live trees are edible, while those that grow on dead trees are poisonous; mushrooms eaten by snails or other small animals, or that are not poisonous to animals such as squirrels, are edible; violet and viscid mushrooms are poisonous; mushrooms whose flesh changes color on cutting are poisonous; mushrooms that exude latex are poisonous; mushrooms that smell like flour are edible; mushrooms that discolor a silver spoon put into the pot while cooking are poisonous, while those that do not are edible; poisonous mushrooms cause milk or egg white to coagulate, while those that do not are edible; brown-gilled mushrooms are edible, but white-gilled mushrooms are poisonous; mushrooms lose their poison if boiled in water with or without salt or vinegar; mushrooms lose their poison through drying; and those that taste good are safe to eat. None of these statements is true!
The only way to know whether a mushroom is safe to eat is to be sure of what you are eating and to have access to reliable advice on its edibility. To sample the "treats" you must know how to identify and avoid the "tricksters."
Unfortunately, many mushrooms do look alike—especially those growing on your lawn at home, in the nearby woods, or on fallen branches. The common edible field mushroom (Agaricus campestris) can be mistaken for numerous brown-gilled species growing in the grass, including poisonous species of Panaeolus and Psilocybe and toxic species of Agaricus. In its button stage the same mushroom, and especially its larger cousin the horse mushroom (A. arvensis), can look every bit like some poisonous Amanita species in their button stage, especially the fly agaric (A. muscaria) and the panther cap (A. pantherina). These are white, and the scales on the caps are sometimes not easily discernible. In addition, fruiting bodies at the button stage can create confusion between the highly prized porcini (Boletus edulis), other edible boletes, and the button stage of poisonous species of Amanita. A number of mushrooms, both edible and poisonous, look just like golf balls in the grass when at their button stage. Amanita at a slightly more advanced stage may take on the shape of an inverted pear and can then be confused with some edible puffballs such as Cal-vatia species and Bovista species. The common field mushroom and the horse mushroom may also be readily confused with a close relative, yellow stainer (Agaricus xanthoderma), which stains yellow quickly on bruising and is renowned for causing stomach disorders.
Within woodlands it is also easy to make mistakes. The honey mushroom (Armillaria mellea), a deadly parasite of trees, grows at the base of infected trees or stumps and is considered by some to be good to eat. It can also superficially resemble the big laughing gym (Gymnopilus junonius), a psychoactive species, or the sulfur tuft (Hypholoma fasciculare), which causes severe gastroenteritis. On dead trees the oyster mushroom Pleurotus ostreatus is a particularly desirable species and is widely grown commercially, but in Australia poisoning incidents have been reported when this species has been mistaken for the morphologically very similar Omphalotus nidi-formis; and in Japan the oyster mushroom has been confused with Lampteromyces japonicus. Similarly, the edible and now commercially produced enokitake (Flammulina velutipes), which naturally grows on decaying tree stumps, must be carefully identified before eating, since it resembles some species of Galerina, which if consumed can prove fatal.
The destroying angel (Amanita virosa) is a fungus to avoid at all costs. Its pure white color belies its toxicity, and it must not be confused with other elegant, white mushrooms that occur in similar habitats, such as some species of Volvariella. Another group of elegant species are the parasol mushrooms (Macrolepiota spp.), which when in their button or juvenile stage are similar to the deadliest of mushrooms: death cap (Amanita phalloides). Tricholoma is also a difficult genus, containing species with whitish or yellow gills with extremely varied appearances. Not only can choice edible species be confused with poisonous ones within the same genus, but some can be readily confused with the most poisonous species of Amanita. Such mistakes are not rare events. In 1996 in the Ukraine ninety-two people died out of eleven hundred who were hospitalized after confusing light-colored Amanita species for edible mushrooms (CBC Newsworld 1996), and at the end of the same year nine people in northern California were hospitalized after consuming Amanita species (CDC 1997). There are similar examples wherever wild mushrooms are consumed. Around nine thousand mushroom poisonings occur in the United States each year alone (Kidcheck 2002).
Among the most visually appealing mushrooms are the chanterelles (Cantharellus spp.), the undersides of their caps covered with blunt, gill-like ridges. Yet here again care needs to be taken so that misidenti-fication does not occur. The highly prized golden chanterelle (Cantharellus cibarius) can be mistaken for Omphalotus olearius (jack-o'-lantern), the consumption of which promotes the most unpleasant of symptoms, including nausea and vomiting (Lincoff and Mitchel 1977). The poisonous brown roll rim (Paxillus involutus) also resembles the chanterelles and the saffron milk cap (Lactarius deliciosus) and should not be eaten. Also similar to P. involutus is false chanterelle (Hygrophoropsis aurantiaca), which is best avoided, since it is known to be hallucinatory.
Some of the most recognizable mushrooms are the morels (Morchella spp.), which are said to look like small human brains and are delicious to eat. Unfortunately they can be confused with another brainlike fungus, the false morel (Gyromitra esculenta), which has the distinction of containing a chemical compound that is the precursor of methylhydrazine, a rocket propellant used by NASA, and that can have lethal effects. Another species of Gyromitra, the hooded false morel (G. infula), has a spectacular appearance but is deadly poisonous when eaten raw. Wrinkled thimble cap (Verpa bohemica), which closely resembles the cap of the edible half-free morel (Morchella semilibera), used to be eaten but is now recognized as poisonous.
Ink caps (Coprinus spp.) are another easily recognizable group of edible mushrooms. The common ink cap (C. atramentarius) is one such species, though it should never be consumed with alcohol and alcohol should not be taken within one to two days after eating it because severe symptoms will result, including an alarmingly rapid pulse rate and nausea.
Puffballs are easily recognizable, but they also need close examination to distinguish the edible from the nonedible varieties. They should not be eaten without first being cut to ensure there are no gills lurking in the button of a puffball look-alike and to discern the color of the flesh. Young fruiting bodies of the earthballs (Scleroderma spp.) have also been mistaken for truffles or puffballs.
Last but certainly not the least is the deceiver (Laccaria laccata), which lives up to its name. Though edible, its great variability in form and even color, depending on the environment, allows for misidenti-fication. It may closely resemble a host of poisonous little brown mushrooms (LBMs), such as Inocybe species and Galerina species.
It is important to remember that there may be large differences in the appearance of the same mushroom in different parts of the world. Even though you may be familiar with and have eaten certain mushrooms in your home country, you cannot assume those of similar appearance in unfamiliar surroundings are edible. Since the edibility of most mushrooms remains unknown, there is plenty of room for error—the look-alike examples given in this section by no means comprise an exhaustive list. Useful generalizations such as being very wary of white-capped and white-gilled mushrooms should be heeded, but also remember that some brown-gilled brown mushrooms are among the deadliest. Err on the side of suspicion and note the old adage, "There are plenty of old mushroom hunters and plenty of bold mushroom hunters, but there are no old, bold mushroom hunters."
Despite the warnings prominently displayed in books on edible mushrooms, mushroom poisonings are not infrequent for those individuals looking for an out-of-body experience or for bona fide mushroom hunters who have failed to follow the rules. Once these unfortunates get to a hospital, the standard treatment is to feed them with activated carbon, which acts like a chemical sponge, and observe their symptoms. From the particular group of symptoms—or syndromes, as they are called—the toxicologist is often able to determine what type of toxin the patient has consumed and hazard a guess at what follow-up treatments may be necessary (Benjamin 1995). However, the toxicologist may not be able to decide just what has been consumed from the symptoms alone, because several genera and many species may contain the same toxin. For example, amatoxins are found not just in Amanita species but also in species of Conocybe, Galerina, and Lepiota.
Detailed descriptions of the syndromes, which toxins are found in which species, treatments used in mushroom poisonings, death rates, and so on, are the subjects of whole books, as with the detailed, though somewhat academic A Colour Atlas of Poisonous Fungi (Bresinsky and Besl 1990) and the very entertaining Mushrooms: Poisons and Panaceas (Benjamin 1995). Consequently this book is restricted to the following brief descriptions of the syndromes. A list of poisonous mushrooms containing the toxins that cause the syndrome follows each description, and additional symptoms caused by the mushrooms are also provided (primarily from Benjamin 1995, Bessette et al. 1997, Both 1993, Bresinsky and Besl 1990, Dhabolt 1993, Imazeki et al. 1988, Lincoff and Mitchel 1977, Miller 1981, Phillips 1981, 1991, Stamets 1996).
Amatoxin (cyclopeptide) syndrome. Symptoms are caused by fungal toxins such as amanitin and amanin, formed of eight amino acids arranged in a ring (cyclopeptides), and develop from six to twenty-four hours after eating the mushrooms. There will be a day or so of violent vomiting, diarrhea, and stomach cramps, followed by lowered blood pressure, accelerated pulse, and dehydration. By this time it may be too late for some patients as many of the amatoxins in the mushroom will have been absorbed from the intestine and will have begun to damage the liver. After the initial stage there is sometimes an apparent recovery, but two to three days later jaundice and liver and kidney failure develop (Bresinsky and Besl 1990, Freedman 1996, Phillips 1981). Death is not infrequent in severe cases. Complete blood dialysis or a liver transplant have been used to treat severe poisonings; other treatments are listed on the Centers for Disease Control and Prevention (CDC) Web site. Amatoxins are not broken down by boiling.
Amanita bisporigera Amanita phalloides Amanita verna Amanita virosa Conocybe filaris Conocybe rugosa Galerina autumnalis Galerina fasciculata Galerina marginata Galerina sulciceps Galerina venenata
Hypholoma fasciculare (other symptoms include gastrointestinal syndrome, impaired vision, paralysis) Lepiota brunneoincarnata Lepiota castanea Lepiota citrophylla Lepiota helveola Lepiota josserandii Lepiota subincarnata
Gyromitrin syndrome. Symptoms begin two to twenty-four hours after ingestion and can include abdominal pain, diarrhea, vomiting, coma, convulsions, delirium, fever, headache, restlessness, respiratory failure, and liver damage leading to jaundice. Kidney failure may also occur, and death is possible in severe cases. The breakdown products of gyromitrin are hydrazines, which are carcinogenic; however, there is no evidence that these cause cancer in humans.
Cudonia circinans Gyromitra ambigua
Gyromitra californica Gyromitra caroliniana Gyromitra esculenta Gyromitra fastigiata Gyromitra gigas Gyromitra infula Gyromitra korfii Gyromitra sphaerospora
Paxillus syndrome (immune hemolytic anemia). In addition to gastrointestinal reactions, Paxillus involutus may cause a potentially fatal immune response that leads to a breakdown of red blood cells in those who have eaten the mushroom, possibly for many years, without experiencing symptoms.
Orellanine syndrome (delayed onset renal failure). Symptoms typically develop from thirty-six hours to three weeks after mushroom ingestion and include progressive kidney failure associated with an insatiable thirst and frequent urination, nausea, vomiting, lethargy, headaches, and shivering without fever or liver damage.
Cortinarius gentilis Cortinarius orellanoides Cortinarius orellanus Cortinarius speciosissimus Cortinarius splendens
Muscarine syndrome. The effects of muscarine poisoning—salivation, lacrimation, urination, defecation, gastrointestinal problems, and emesis—have given rise to the acronym SLUDGE. Other symptoms include decreased blood pressure, profuse sweating, and death due to respiratory failure.
Boletus pulcherrimus (other symptoms include gastrointestinal syndrome) Clitocybe aurantiacum Clitocybe candicans Clitocybe dealbata
Clitocybe dilatata Clitocybe ericetosa Clitocybe gibba Clitocybe nebularis Clitocybe phaeophthalma Clitocybe phyllophila Clitocybe rivulosa Clitocybe truncicola
Entoloma rhodopolium (other symptoms include gastrointestinal syndrome) Inocybe bongardii Inocybe dulcamara Inocybe fastigiata Inocybe geophylla Inocybe godeyi Inocybe griseolilacina Inocybe hirtella Inocybe lacera Inocybe maculata Inocybe napipes Inocybe patouillardii Inocybe praetervisa Inocybe sororia Mycena pura
Hallucinogenic syndrome. Symptoms, which develop within an hour and last for up to six hours, are similar to those produced by hallucinogenic chemicals like lysergide. They include vivid hallucinations, lack of contact with reality, seizures, prolonged reaction time, increased heart rate, dilation of pupils, and increased blood pressure.
Conocybe cyanopus Gymnopilus junonius Inocybe corydalina Lycoperdon marginatum Panaeolus ater Panaeolus campanulatus Panaeolus foenisecii Panaeolus papilionaceus Panaeolus retirugis Panaeolus sphinctrinus
Panaeolus subbalteatus Pluteus cyanopus Pluteus salicinus Pluteus villosus Psilocybe argentipes Psilocybe baeocystis Psilocybe caerulescens Psilocybe caerulipes Psilocybe coprophila Psilocybe crobula Psilocybe cubensis Psilocybe fasciculata Psilocybe merdaria Psilocybe subaeruginascens
Stropharia coronilla (other symptoms include gastrointestinal syndrome, malaise, headache, ataxia, dizziness)
Pantherine syndrome. There is a rapid onset of symptoms, including intoxication, ataxia, dizziness, lethargy (but sometimes with periods of manic behavior), nausea, vomiting, muscle cramps, tremor, seizures, hallucinations, and dilated or restricted pupils, with the patient finally moving into a coma-like state.
Amanita cothurnata Amanita crenulata Amanita gemmata Amanita muscaria Amanita pantherina Amanita regalis Amanita solitaria Tricholoma muscarium
Gastrointestinal syndrome. The main symptoms, which can occur from a few minutes to a few hours after a meal, include abdominal pain followed by nausea, profuse sweating, vomiting, and diarrhea.
Agaricus hondensis Agaricus placomyces Agaricus praeclaresquamosus Agaricus xanthoderma
Amanita brunnescens Amanita chlorinosma Amanita flavoconia Amaniata flavorubescens Amanita frostiana Amanita parcivolvata Armillaria mellea Boletus erythropus Boletus haematinus
Boletus luridus (other symptoms include coprine syndrome) Boletus pulcherrimus (other symptoms include muscarine syndrome) Boletus sensibilis Bondarzewia berkeleyi Chlorophyllum molybdites
Clitocybe acromelalga (other symptoms include sharp pains, red swelling of hands and feet one week after ingestion) Collybia acervata Collybia dryophila Cortinarius cinnamomeus Dermocybe sanguinea
Entoloma rhodopolium (other symptoms include muscarine syndrome) Entoloma sinuatum Gomphus bonari
Gomphus floccosus (other symptoms include neurological impairment) Gomphus fujisanensis
Gomphus kauffmanii (other symptoms include neurological impairment) Hebeloma crustuliniforme Hebeloma mesophaeum Hebeloma sinapizans Hebeloma vinosophyllum Hygrocybe conica Hygrocybe ovina
Hypholoma fasciculare (other symptoms include amatoxin syndrome, impaired vision, paralysis) Lactarius chrysorheus Lactarius helvus Lactarius piperatus
Lactarius pubescens Lactarius repraesentaneus Lactarius rufus Lactarius scrobiculatus Lactarius torminosus Lactarius uvidus Laetiporus sulphureus Lampteromyces japonicus Lepiota clypeolaria Lepiota cristata Lepiota lutea
Lespista irina (other symptoms include neurological impairment)
Paxillus involutus (other symptoms include paxillus syndrome;
possibly also a mutagen and carcinogen) Phaeolepiota aurea Phaeolus schweinitzii
Pholiota squarrosa (other symptoms include coprine syndrome)
Scleroderma cepa (other symptoms include spasms, tingling sensations, rigidity) Scleroderma citrinum
Stropharia coronilla (other symptoms include hallucinogenic syndrome, malaise, headache, ataxia, dizziness) Suillus granulatus Tricholoma album Tricholoma inamoenum Tricholoma pessundatum Tricholoma pardinum Tricholoma saponaceum
Tricholoma sulphureum (other symptoms include neurological impairment) Tricholoma venenata Tricholoma zelleri
Tricholomopsis platyphylla (other symptoms include muscle cramps) Verpa bohemica Verpa conica
Alcohol dehydrogenase inhibition
Coprine (Antabuse) syndrome. Coprine may inhibit the function of alcohol dehydrogenase, an enzyme needed in the conversion of alcohol to acetic acid. The symptoms are similar to those of Antabuse (disul-firam), which is used for the treatment of alcoholism. Symptoms develop soon after ingestion and include severe headaches, rapid pulse, flushed face and chest, sweating, low blood pressure, confusion, nausea, and vomiting.
Boletus luridus (other symptoms include gastrointestinal syndrome)
Pholiota squarrosa (other symptoms include gastrointestinal syndrome) Tricholoma aurantium
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