:Gyromitra esculenta

The fungus was first described in 1800, by mycologist Christian Hendrik Persoon, as Helvella esculenta,Persoon CH (1800) Comm. Schaeff. Icon. Pict.: 64 and gained its current accepted binomial name when the Swedish mycologist Elias Magnus Fries placed it in the genus Gyromitra in 1849.Fries EM (1849) Summa veg. Scand., Section Post. (Stockholm):p. 346 The genus name is derived from the Greek terms gyros/γυρος "round" and mitra/μιτρα "headband".{{cite book |authorlink=Henry George Liddell |last1=Liddell |first1=Henry G. |author2link=Robert Scott (philologist) |first2=Robert |last2=Scott | year = 1980 | title = A Greek–English Lexicon |edition=Abridged | publisher = Oxford University Press | location =Oxford | isbn= 978-0-19-910207-5|title-link=A Greek–English Lexicon }} Its specific epithet is derived from the Latin esculentus, "edible".{{cite book | last = Simpson | first = D.P. | title = Cassell's Latin Dictionary | publisher = Cassell | year = 1979 | edition = 5th | location = London | pages = 883 | isbn= 978-0-304-52257-6}}

It is known by a variety of common descriptive names such as "brain mushroom",{{cite book |last=Arora |first=David |authorlink=David Arora |year=1986 |title=Mushrooms Demystified: a comprehensive guide to the fleshy fungi |edition=2nd |location=Berkeley |publisher=Ten Speed Press |isbn=978-0-89815-169-5 |pages=[https://archive.org/details/mushroomsdemysti00aror_0/page/801 801–02] |url-access=registration |url=https://archive.org/details/mushroomsdemysti00aror_0/page/801 }} "turban fungus", elephant ears,{{cite journal |last=Dearness |first=J |year=1924|title=Gyromitra poisoning |journal=Mycologia |volume=16|pages=143–176 |doi=10.2307/3753381 |issue=4 |jstor=3753381}} or "beefsteak mushroom/morel", although beefsteak mushroom can also refer to the much choicer edible basidiomycete Fistulina hepatica.{{sfn|Ammirati|Traquair|Horgen|1985|p=122}} Dating from the 19th century, the German term {{lang|de|lorchel}} is a result of the older {{lang|de|lorche}}, itself from the 18th century Low German {{lang|nds|Lorken}}, aligning with the similar-sounding (and similar-looking) {{lang|nds|morchel}}.{{cite book |title=Duden 07 – Das Herkunftswörterbuch – Etymologie der deutschen Sprache |year=2001|publisher=Dudenverlag |language=German |isbn= 978-3-411-04074-2 |author= Dudenredaktion, Bibliographisches Institut, Mannheim}}{{cite book | last = North| first = Pamela | year = 1967 | title = Poisonous Plants and Fungi in colour | publisher = Blandford Press & Pharmacological Society of Great Britain |page=109|oclc=955264}}

Gyromitra esculenta is a member of a group of fungi known as "false morels", so named for their resemblance to the highly regarded true morels of the genus Morchella. The grouping includes other species of the genus Gyromitra, such as G. infula (elfin saddle), G. caroliniana and G. gigas (snow morel). While some of these species contain little to no gyromitrin, many guidebooks recommend treating them all as poisonous, since their similar appearance and significant intraspecific variation can make reliable identification difficult.{{Cite web|author=Departament de Salut, Generalitat de Catalunya |title=Bolets |url=http://www.gencat.cat/salut/depsalut/html/ca/dir2155/csam_6.htm |access-date=20 March 2009 |language=ca |url-status=dead |archive-url=https://web.archive.org/web/20090308071936/http://www.gencat.cat/salut/depsalut/html/ca/dir2155/csam_6.htm |archive-date=8 March 2009 }} The toxic qualities of G. esculenta may be reduced by cooking, but possibly not enough to prevent poisoning from repeated consumption.{{cite book |last=Phillips |first=Roger |title=Mushrooms and Other Fungi of North America |url=https://archive.org/details/mushroomsotherfu0000phil |url-access=registration |year=2010 |publisher=Firefly Books |location=Buffalo, NY |isbn=978-1-55407-651-2 |page=[https://archive.org/details/mushroomsotherfu0000phil/page/363 363]}}

The more distantly related ascomycete mushrooms of the genus Verpa, such as V. bohemica and V. conica, are also known as false morels, early morels or thimble morels; like the Gyromitra, they are eaten by some and considered poisonous by others.{{harvnb|Benjamin|1995|p=267}}

The genus Gyromitra had been classically considered part of the family Helvellaceae, along with the similar-looking elfin saddles of the genus Helvella. Analysis of the ribosomal DNA of many of the Pezizales showed G. esculenta and the other false morels to be only distantly related to the other members of the Helvellaceae and instead most closely related to the genus Discina, forming a clade which also contains Pseudorhizina and Hydnotrya. Thus the four genera are now included in the family Discinaceae.{{cite journal |last=O'Donnell |first=Kerry|author2=Cigelnik, Elizabeth|author3=Weber, Nancy S.|author4=Trappe, James M. |year=1997|title=Phylogenetic relationships among ascomycetous truffles and the true and false morels inferred from 18S and 28S ribosomal DNA sequence analysis |journal=Mycologia |volume=89 |issue=1 |pages=48–65 |doi=10.2307/3761172 |jstor=3761172}}

Image:2007-04-02 Gyromitra esculenta cropped.jpg]]

Resembling a brain, the irregularly shaped cap may be up to {{convert|10|cm|in|frac=2|abbr=off}} high and {{convert|15|cm|in|frac=2|abbr=on}} wide. Initially smooth, it becomes progressively more wrinkled as it grows and ages. The cap colour may be various shades of reddish-, chestnut-, purplish-, bay-, dark or sometimes golden-brown; it darkens to black in age.{{cite book |last1=Trudell |first1=Steve |url=https://books.google.com/books?id=WevHvt6Tr8kC |title=Mushrooms of the Pacific Northwest |last2=Ammirati |first2=Joe |publisher=Timber Press |year=2009 |isbn=978-0-88192-935-5 |series=Timber Press Field Guides |location=Portland, OR |pages=279–280 |language=en}} Specimens from California may have more reddish-brown caps. Attached to the cap at several points, the stipe is {{convert|3|-|6|cm|in|frac=2|abbr=on}} high and {{convert|1|-|5|cm|in|frac=4|abbr=on}} wide.{{Cite book |last1=Davis |first1=R. Michael |title=Field Guide to Mushrooms of Western North America |last2=Sommer |first2=Robert |last3=Menge |first3=John A. |publisher=University of California Press |year=2012 |isbn=978-0-520-95360-4 |location=Berkeley |pages=394–395 |oclc=797915861}} G. esculenta has been reported to have a solid stipe whereas those of true morels (Morchella spp.) are hollow, although a modern source says it is hollow as well. The smell can be pleasant and has been described as fruity, and the fungus is mild-tasting. The spore print is whitish, with transparent spores that are elliptical and 17–22 μm in length.{{cite book |last=Zeitlmayr |first=Linus |title=Wild Mushrooms:An Illustrated Handbook |publisher=Garden City Press |year=1976 |isbn=978-0-584-10324-3 |location=Hertfordshire |pages=112}}

G. esculenta resembles the various species of true morel, although the latter are more symmetric and look more like pitted gray, tan, or brown sponges. Its cap is generally darker and larger.{{sfn|Ammirati|Traquair|Horgen|1985|p=121}}

G. gigas, G. infula and G. ambigua in particular are similar, the latter two being toxic to humans.

G. esculenta grows on sandy soil in temperate coniferous forest and occasionally in deciduous woodlands. Among conifers it is mostly found under pines (Pinus spp.), but also sometimes under aspens (Populus spp.).{{cite book |title=How to Know the Non-Gilled Fleshy Fungi |vauthors=Smith HV, Smith AH |year=1973 |publisher=Wm. C. Brown Co. |location=Dubuque, Il |isbn=978-0-697-04866-0}} The hunting period is from April to July, earlier than for other species, and the fungus may even sprout up with the melting snow. It can be abundant in some years and rare in others. The mushroom is more commonly found in places where ground has been disturbed, such as openings, rivulets, washes, timber clearings, plowed openings, forest fire clearings, and roadsides.{{cite book |last1=Nilsson |first1=S. |last2=Persson |first2=O. |year=1977 |title=Fungi of Northern Europe 1: Larger Fungi (Excluding Gill Fungi) |pages=34–35 |publisher=Penguin |isbn=978-0-14-063005-3}} Enthusiasts in Finland have been reported burying newspaper inoculated with the fungus in the ground in autumn and returning the following spring to collect mushrooms.{{cite web |url=http://www.mushroomexpert.com/gyromitra_esculenta.html |title=Gyromitra esculenta |access-date=11 May 2008 |author=Kuo M |date=January 2005 |website=MushroomExpert.Com Web site |publisher=self}}

Although more abundant in montane and northern coniferous woodlands such as the Sierra Nevada and the Cascade Range in northwestern North America, Gyromitra esculenta is found widely across the continent, as far south as Mexico.{{cite journal |last=Medel |first=Rosario|year=2005|title=A review of the genus Gyromitra (Ascomycota, Pezizales, Discinaceae) in Mexico |journal=Mycotaxon |volume=94|pages=103–10}} It is also common in Central Europe, less abundant in the east, and more in montane areas than lowlands.{{cite book |title=The Great Encyclopedia of Mushrooms |last=Lamaison |first=Jean-Louis |author2=Polese, Jean-Marie |year=2005 |publisher=Könemann |isbn=978-3-8331-1239-3|pages=230}} It has been recorded from Northern Ireland,{{cite web|title = Northern Ireland's Herbarium Specimens|publisher = Northern Ireland Fungus Group|year = 2007|url = http://www.nifg.org.uk/herbarium.htm|access-date = 6 March 2008|archive-url = https://web.archive.org/web/20190207015333/http://www.nifg.org.uk/herbarium.htm|archive-date = 7 February 2019|url-status = dead}} from Uşak Province in Western Turkey,{{cite journal|vauthors=Türkoglu A, Alli H, Işiloğlu M, Yağiz D, Gezer K |date=February 2008 |title=Macrofungal diversity of Uşak province in Turkey |journal=Mycotaxon |volume=103 |pages=1–11 |url=http://egitim.selcuk.edu.tr/fen/yagiz/pdf/mycotaxon08-002.pdf |access-date=7 March 2008 |url-status=dead |archive-url=https://web.archive.org/web/20090225142515/http://egitim.selcuk.edu.tr/fen/yagiz/pdf/mycotaxon08-002.pdf |archive-date=25 February 2009 }} and from the vicinity of Kaş in the Antalya Province of Turkey's southern coast.{{cite journal|author=Gezer K |year=2000 |title=Contributions to the Macrofungi Flora of Antalya Province |journal=Turkish Journal of Botany |volume=24 |issue=5 |pages=293–98 |url=http://mistug.tubitak.gov.tr/bdyim/abs.php?dergi=bot&rak=97069 |access-date=16 February 2008 |url-status=dead |archive-url=https://web.archive.org/web/20090323134146/http://mistug.tubitak.gov.tr/bdyim/abs.php?dergi=bot&rak=97069 |archive-date=23 March 2009 }}

Image:False morels for sale - don't touch.jpg]]

Toxic reactions have been known for at least a hundred years. Experts speculated the reaction was more of an allergic one specific to the consumer, or a misidentification, rather than innate toxicity of the fungus, due to the wide range in effects seen. Some would suffer severely or perish while others exhibited no symptoms after eating similar amounts of mushrooms from the same dish. Yet others would be not poisoned after eating G. esculenta for many years.{{harvnb|Benjamin|1995|p=264}} However, the fungus is now widely recognized as potentially deadly.{{harvnb|Benjamin|1995|p=265}}

Gyromitra esculenta contains levels of the poison gyromitrin that vary locally among populations; although these mushrooms are only rarely involved in poisonings in either North America or western Europe, intoxications are seen frequently in eastern Europe and Scandinavia.{{cite journal |author=Diaz JH |title=Syndromic diagnosis and management of confirmed mushroom poisonings |journal=Critical Care Medicine |volume=33 |issue=2 |pages=427–36 |year=2005 |pmid=15699849|doi=10.1097/01.CCM.0000153531.69448.49|s2cid=24492593 }} A 1971 Polish study reported at the time that the species accounted for up to 23% of mushroom fatalities each year. Death rates have dropped since the mid-twentieth century; in Sweden poisoning is common, though life-threatening poisonings have not been detected and there was no fatality reported over the 50 years from 1952 to 2002. Gyromitra poisonings are rare in Spain, due to the widespread practice of drying the mushrooms before preparation and consumption,{{Cite web | url = http://tratado.uninet.edu/c101102.html | title = Intoxicaciones por setas (micetismos) | access-date = 20 March 2009 | author1 = Palomar Martínez, M. | author2 = Piqueras Carrasco, J. | year = 1999 | archive-url = https://web.archive.org/web/20090322112813/http://tratado.uninet.edu/c101102.html | archive-date = 22 March 2009 | url-status = dead }} {{Clarify|date=January 2025|text=but has a mortality rate of about 25%}}.{{Cite book | author = Lloret i Carbó, Josep | title = Protocolos terapéuticos de urgencias | url = https://books.google.com/books?id=XUcDIfU6yxAC&q=bolet+de+greix&pg=PA649 | page = 649 | isbn = 978-84-458-1418-5 | edition = 4ª | publisher = Elsevier | year = 2004}}

A lethal dose of gyromitrin has been estimated to be 10–30 mg/kg for children and 20–50 mg/kg in adults. These doses correspond to around {{convert|0.2|-|0.6|kg|lboz|0|abbr=on}} and {{convert|0.4|-|1|kg|lboz|abbr=on}} of fresh mushroom respectively. Evidence suggests that children are more severely affected; it is unclear whether this is due to a larger weight consumed per body mass ratio or to differences in enzyme and metabolic activity.

Populations of G. esculenta appear to vary geographically in their toxicity. A French study has shown that mushrooms collected at higher altitudes have lower concentrations of toxin than those from lower elevations,{{harvnb|Benjamin|1995|p=272}} and there is some evidence that fungi west of the Rocky Mountains in North America contain less toxin than those to the east.{{harvnb|Benjamin|1995|p=140}} However, poisonings in the USA have been reported, although less frequently than in Europe.{{cite journal |vauthors=Balterowich L, Blaney B, White S |year=1996 |title=Acute hepatotoxicity following ingestion of Gyromitra esculenta(false morel) mushrooms |journal=Journal of Toxicology. Clinical Toxicology |volume=34 |issue=5 |pages=602 |url=http://pdfserve.informaworld.com/316802_751308121_784519284.pdf |access-date=7 November 2008 |archive-date=26 March 2009 |archive-url=https://web.archive.org/web/20090326054827/http://pdfserve.informaworld.com/316802_751308121_784519284.pdf |url-status=dead }}

Image:Methylhydrazine-3D-balls.png (C H₃N₂H₃), a toxic metabolite]]

The identity of the toxic constituents eluded researchers until 1968, when acetaldehyde N-methyl-N-formylhydrazone, better known as gyromitrin, was isolated.{{cite journal |vauthors=List PH, Luft P |title=[Gyromitrin, the poison of Gyromitra esculenta. 16. On the fungi contents] |language=German |journal=Archiv der Pharmazie |volume=301 |issue=4 |pages=294–305 |year=1968 |pmid=5244383 |doi=10.1002/ardp.19683010410|s2cid=95372473 }} Gyromitrin is a volatile, water-soluble hydrazine compound hydrolyzed in the body into N-methyl-N-formylhydrazine (MFH) then monomethylhydrazine (MMH). Other N-methyl-N-formylhydrazone derivatives have been isolated in subsequent research, although they are present in smaller amounts. These other compounds would also produce monomethylhydrazine when hydrolyzed, although it remains unclear how much each contributes to the false morel's toxicity.{{cite journal |author=Pyysalo H |title=Some new toxic compounds in false morels, Gyromitra esculenta |journal=Naturwissenschaften |volume=62 |issue=8 |pages=395 |year=1975 |pmid=1238907 |doi=10.1007/BF00625355|bibcode=1975NW.....62..395P |s2cid=178876 }}

The toxins react with pyridoxal-5-phosphate—the activated form of pyridoxine (vitamin B₆)—and form a hydrazone. This reduces production of the neurotransmitter GABA via decreased activity of glutamic acid decarboxylase,{{cite journal |author=Cornish HH |title=The role of vitamin B6 in the toxicity of hydrazines |journal=Annals of the New York Academy of Sciences |volume=166 |issue=1 |pages=136–45 |year=1969 |pmid=5262010|doi=10.1111/j.1749-6632.1969.tb54264.x|bibcode=1969NYASA.166..136C |hdl=2027.42/73785 |s2cid=34449326 |hdl-access=free }} producing the neurological symptoms. MMH also causes oxidative stress leading to methemoglobinemia. Inhibition of diamine oxidase (histaminase) elevates histamine levels resulting in headaches, nausea, vomiting, and abdominal pain.{{cite journal |vauthors=Biegański T, Braun R, Kusche J |title=N-methyl-N-formylhydrazine: a toxic and mutagenic inhibitor of the intestinal diamine oxidase |journal=Agents and Actions |volume=14 |issue=3–4 |pages=351–5 |year=1984 |pmid=6428190 |doi=10.1007/BF01973825|s2cid=22859426 }}

MFH, as a mushroom component and an intermediary product of gyromitrin hydrolysis,{{cite journal |last1=Nagel |first1=Donald |last2=Wallcave |first2=L. |last3=Toth |first3=Bela |last4=Kupper |first4=Robert |title=Formation of Methylhydrazine from Acetaldehyde N-Methyl-N-formylhydrazone, a Component of Gyromitra esculenta |journal=Cancer Research |date=1977 |volume=37 |issue=9 |pages=3458–60 |pmid=18281 }} has toxicities of its own. MFH undergoes cytochrome P450-regulated oxidative metabolism which, via reactive nitrosamide intermediates, leads to formation of methyl radicals which lead to liver necrosis.{{cite journal |vauthors=Braun R, Greeff U, Netter KJ |title=Indications for nitrosamide formation from the mushroom poison gyromitrin by rat liver microsomes |journal=Xenobiotica |volume=10 |issue=7–8 |pages=557–64 |year=1980 |pmid=7445522 |doi=10.3109/00498258009033790}}{{cite journal |vauthors=Braun R, Greeff U, Netter KJ |title=Liver injury by the false morel poison gyromitrin |journal=Toxicology |volume=12 |issue=2 |pages=155–63 |year=1979 |pmid=473232|doi=10.1016/0300-483X(79)90042-8}}

The symptoms of poisoning are typically gastrointestinal and neurological.{{cite journal |vauthors=Karlson-Stiber C, Persson H |title=Cytotoxic fungi—an overview |journal=Toxicon |volume=42 |issue=4 |pages=339–49 |year=2003 |pmid=14505933 |doi=10.1016/S0041-0101(03)00238-1|bibcode=2003Txcn...42..339K }} Symptoms occur within 6–12 hours of consumption, although cases of more severe poisoning may present sooner—as little as 2 hours after ingestion. Initial symptoms are gastrointestinal, with sudden onset of nausea, vomiting, and watery diarrhea which may be bloodstained. Dehydration may develop if the vomiting or diarrhea is severe. Dizziness, lethargy, vertigo, tremor, ataxia, nystagmus, and headaches develop soon after; fever often occurs, a distinctive feature which does not develop after poisoning by other types of mushrooms.{{harvnb|Benjamin|1995|p=273}} In most cases of poisoning, symptoms do not progress from these initial symptoms, and patients recover after 2–6 days of illness.

In some cases there may be an asymptomatic phase following the initial symptoms which is then followed by more significant toxicity including kidney damage,{{cite journal |vauthors=Braun R, Kremer J, Rau H |title=Renal functional response to the mushroom poison gyromitrin |journal=Toxicology |volume=13 |issue=2 |pages=187–96 |year=1979 |pmid=42171 |doi=10.1016/s0300-483x(79)80022-0|bibcode=1979Toxgy..13..187B }} liver damage, and neurological dysfunction including seizures and coma.{{cite journal |vauthors=Michelot D, Toth B |title=Poisoning by Gyromitra esculenta—a review |journal=Journal of Applied Toxicology |volume=11 |issue=4 |pages=235–43 |year=1991 |pmid=1939997|doi=10.1002/jat.2550110403|s2cid=7994829 }} These signs usually develop within 1–3 days in serious cases. The patient develops jaundice and the liver and spleen become enlarged; in some cases blood sugar levels will rise (hyperglycemia) and then fall (hypoglycemia) and liver toxicity is seen. Additionally intravascular hemolysis causes destruction of red blood cells resulting in increase in free hemoglobin and hemoglobinuria which can lead to renal toxicity or kidney failure. Methemoglobinemia may also occur in some cases. This is where higher than normal levels of methemoglobin, which is a form of hemoglobin that can not carry oxygen, are found in the blood. It causes the patient to become short of breath and cyanotic.{{harvnb|Benjamin|1995|p=274}} Cases of severe poisoning may progress to a terminal neurological phase, with delirium, muscle fasciculations and seizures, and mydriasis progressing to coma, circulatory collapse, and respiratory arrest.{{cite journal |vauthors=Giusti GV, Carnevale A |title=A case of fatal poisoning by Gyromitra esculenta |journal=Archives of Toxicology |volume=33 |issue=1 |pages=49–54 |year=1974 |doi=10.1007/BF00297052 |pmid=4480349|bibcode=1974ArTox..33...49G |s2cid=6836725 }} Death may occur from five to seven days after consumption.{{cite journal |vauthors=Hanrahan JP, Gordon MA |title=Mushroom poisoning. Case reports and a review of therapy |journal=JAMA |volume=251 |issue=8 |pages=1057–61 |year=1984 |pmid=6420582|doi=10.1001/jama.251.8.1057}}

Treatment is mainly supportive; gastric decontamination with activated charcoal may be beneficial if medical attention is sought within a few hours of consumption. However, symptoms often take longer than this to develop, and patients do not usually present for treatment until many hours after ingestion, thus limiting its effectiveness.{{cite journal |author=Köppel C |title=Clinical symptomatology and management of mushroom poisoning |journal=Toxicon |volume=31 |issue=12 |pages=1513–40 |year=1993 |pmid=8146866|doi=10.1016/0041-0101(93)90337-I|bibcode=1993Txcn...31.1513K }} Patients with severe vomiting or diarrhea can be rehydrated with intravenous fluids.{{cite journal |author=Lampe KF |title=Toxic fungi |journal=Annual Review of Pharmacology and Toxicology |volume=19 |issue=1|pages=85–104 |year=1979 |pmid=378111 |doi=10.1146/annurev.pa.19.040179.000505}} Monitoring of biochemical parameters such as methemoglobin levels, electrolytes, liver and kidney function, urinalysis, and complete blood count is undertaken and any abnormalities are corrected. Dialysis can be used if kidney function is impaired or the kidneys are failing. Hemolysis may require a blood transfusion to replace the lost red blood cells, while methemoglobinemia is treated with intravenous methylene blue.{{harvnb|Benjamin|1995|p=276}}

Pyridoxine, also known as vitamin B6, can be used to counteract the inhibition by MMH on the pyridoxine-dependent step in the synthesis of the neurotransmitter GABA. Thus GABA synthesis can continue and symptoms are relieved.{{cite journal |vauthors=Wright AV, Niskanen A, Pyysalo H, Korpela H |title=Amelioration of toxic effects of ethylidene gyromitrin (false morel poison) with pyridoxine chloride|journal=Journal of Food Safety |volume=3 |issue=3|pages=199–203|year=1981 |doi=10.1111/j.1745-4565.1981.tb00422.x}} Pyridoxine, which is only useful for the neurological symptoms and does not decrease hepatic toxicity,{{cite journal |vauthors=Toth B, Erickson J |title=Reversal of the toxicity of hydrazine an analogues by pyridoxine hydrochloride |journal=Toxicology |volume=7 |issue=1 |pages=31–36 |year=1977 |pmid=841582|doi=10.1016/0300-483X(77)90035-X|bibcode=1977Toxgy...7...31T }} is given at a dose of 25 mg/kg; this can be repeated up to a maximum total of 15 to 30 g daily if symptoms do not improve.{{cite journal |doi=10.1056/NEJM197604222941708 |vauthors=Kirklin JK, Watson M, Bondoc CC, Burke JF |title=Treatment of hydrazine-induced coma with pyridoxine |journal=The New England Journal of Medicine |volume=294 |issue=17 |pages=938–9 |year=1976 |pmid=815813}} Benzodiazepines are given to control seizures; as they also modulate GABA receptors they may potentially increase the effect of pyridoxine. Additionally MMH inhibits the chemical transformation of folic acid into its active form, folinic acid, this can be treated by folinic acid given at 20–200 mg daily.

Lagrange et al. presented in 2018 a link between life-long foraging for G. esculenta and amyotrophic lateral sclerosis (ALS) in French Alps populations.{{cite book |last1=Horowitz |first1=Keahi M. |last2=Kong |first2=Erwin L. |last3=Horowitz |first3=B. Zane |title=StatPearls |date=2023 |publisher=StatPearls Publishing |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK470580/ |chapter=Gyromitra Mushroom Toxicity |pmid=29262102 }} Similar ALS clusters possibly related to mushrooms are found near the Aosta Valley (Italy), in Sardinia, and in Michigan.{{cite journal |last1=Spencer |first1=PS |last2=Palmer |first2=VS |last3=Kisby |first3=GE |last4=Lagrange |first4=E |last5=Horowitz |first5=BZ |last6=Valdes Angues |first6=R |last7=Reis |first7=J |last8=Vernoux |first8=JP |last9=Raoul |first9=C |last10=Camu |first10=W |title=Early-onset, conjugal, twin-discordant, and clusters of sporadic ALS: Pathway to discovery of etiology via lifetime exposome research. |journal=Frontiers in Neuroscience |date=2023 |volume=17 |pages=1005096 |doi=10.3389/fnins.2023.1005096 |pmid=36860617 |pmc=9969898 |doi-access=free }}

Monomethylhydrazine,{{cite journal |vauthors=Toth B, Shimizu H |title=Methylhydrazine tumorigenesis in Syrian golden hamsters and the morphology of malignant histiocytomas |journal=Cancer Research |volume=33 |issue=11 |pages=2744–53 |year=1973 |pmid=4355982 |url=https://aacrjournals.org/cancerres/article/33/11/2744/479279/Methylhydrazine-Tumorigenesis-in-Syrian-Golden }} gyromitrin,{{cite journal |vauthors=Toth B, Smith JW, Patil KD |title=Cancer induction in mice with acetaldehyde methylformylhydrazone of the false morel mushroom |journal=Journal of the National Cancer Institute |volume=67 |issue=4 |pages=881–87 |year=1981 |pmid=6944556 |doi=10.1093/jnci/67.4.881}} raw Gyromitra esculenta,{{cite journal |vauthors=Toth B, Patil K, Pyysalo H, Stessman C, Gannett P |title=Cancer induction in mice by feeding the raw false morel mushroom Gyromitra esculenta |journal=Cancer Research |volume=52 |issue=8 |pages=2279–84 |year=1992 |pmid=1559231}} and N-methyl-N-formylhydrazine{{cite journal |vauthors=Toth B, Nagel D |title=Tumors induced in mice by N-methyl-N-formylhydrazine of the false morel Gyromitra esculenta |journal=Journal of the National Cancer Institute |volume=60 |issue=1 |pages=201–04 |year=1978 |pmid=628017|doi=10.1093/jnci/60.1.201}}{{cite journal |vauthors=Toth B, Patil K, Erickson J, Kupper R |title=False morel mushroom Gyromitra esculenta toxin: N-methyl-N-formylhdrazine carcinogenesis in mice |journal=Mycopathologia |volume=68 |issue=2 |pages=121–28 |year=1979 |pmid=573857 |doi=10.1007/BF00441091|s2cid=11914469 }} have been shown to be carcinogenic in experimental animals. Although Gyromitra esculenta has not been observed to cause cancer in humans, it is possible there is a carcinogenic risk for people who ingest these types of mushrooms. Even small amounts may have a carcinogenic effect.{{harvnb|Benjamin|1995|pp=128–9}} At least 11 different hydrazones have been isolated from G. esculenta, and it is not known if all potential carcinogens can be completely removed by parboiling.{{cite book |last=Dart |first=Richard C. |title=Medical toxicology |publisher=Williams & Wilkins |year=2004 |isbn=978-0-7817-2845-4 |location=Philadelphia |pages=1719–35 |chapter=Mushrooms}}

Image:False morels for sale in Helsinki 2.jpg, Finland with compulsory preparation instructions/safety datasheet]]

Despite its recognized toxicity, Gyromitra esculenta is marketed and consumed in several countries or states in Europe and North America. It was previously consumed in Germany, with fungi picked in and exported from Poland; more recently, however, Germany and Switzerland discouraged consumption by prohibiting its sale.{{cite book |vauthors=Bresinsky A, Besl H | title = A Colour Atlas of Poisonous Fungi | year = 1990 | publisher = Wolfe Publishing | pages=62–68|isbn = 978-0-7234-1576-3}} Similarly in Sweden, the Swedish National Food Administration warns that it is not fit for human consumption,{{cite web|last=Andersson |first=Christer |title=Stenmurklan – olämplig att äta |website=Livsmedelsverket (National Food Administration) |publisher=Swedish National Food Administration |year=2007 |url=http://www.slv.se/templates/SLV_Page.aspx?id=11600&epslanguage=SV |access-date=7 March 2008 |language=sv |url-status=dead |archive-url=https://web.archive.org/web/20071006105549/http://www.slv.se/templates/SLV_Page.aspx?id=11600&epslanguage=SV |archive-date=6 October 2007 }} and restricts purchase of fresh mushrooms to restaurants alone.{{cite web|last=Andersson |first=Christer |title=Stenmurkla – frågor och svar |website=Livsmedelsverket (National Food Administration) |publisher=Swedish National Food Administration |year=2007 |url=http://www.slv.se/sv/Fragor--svar/Fragor-och-svar/Saker-mat/Stenmurkla---fragor-och-svar/ |access-date=4 March 2012 |language=sv |url-status=dead |archive-url=https://web.archive.org/web/20120706234254/http://www.slv.se/sv/Fragor--svar/Fragor-och-svar/Saker-mat/Stenmurkla---fragor-och-svar/ |archive-date=6 July 2012 }} The mushroom is still highly regarded and consumed in Bulgaria, being sold in markets and picked for export there.{{cite web |vauthors=Drumeva-Dimcheva M, Gyosheva-Bogoeva M | title = Section One: Bulgaria's Biological Diversity – The Macromycetes Fungi of Bulgaria | website = Bulgaria's Biological Diversity: Conservation Status and Needs Assessment | publisher = Biodiversity Support Program (WWF, The Nature Conservancy, and World Resources Institute Consortium) | year = 1998 | url = http://www.worldwildlife.org/bsp/publications/europe/bulgaria/bulgaria1.html | access-date = 2008-03-06}} In some countries such as Spain, especially in the eastern Pyrenees, they are traditionally considered a delicacy, and many people report consuming them for many years with no ill effects.{{cite web |url=http://www.elcargol.com/bolets.htm |title=Bolets |access-date=8 June 2008 |publisher=Revista el cargol |year=2008 |url-status=dead |archive-url=https://web.archive.org/web/20070128174400/http://www.elcargol.com/bolets.htm |archive-date=28 January 2007 }} Despite this, the false morel is listed as hazardous in official mushroom lists published by the Catalan Government and sale to the public is prohibited throughout Spain.{{Cite journal |url=http://www.boe.es/boe/dias/2004/02/06/pdfs/A05061-05065.pdf|title= ORDEN SCO/190/2004, de 28 de enero, por la que se establece la lista de plantas cuya venta al público queda prohibida o restringida por razón de su toxicidad | journal = BOE | issue = 32 | pages = 5061–65 |access-date=8 June 2008 | author=Ministerio de Sanidad y Consumo | date=6 February 2004|language=es}} Outside of Europe, G. esculenta is consumed in the Great Lakes region and some western states in the United States.{{cite journal |last=Simons |first=DM |year=1971|title=The Mushroom Toxins |journal=Delaware Medical Journal |volume=43 |pages=177–87}}

Selling and purchasing fresh false morels is legal in Finland, where it is highly regarded.{{cite journal |last=Härkönen |first=M |year=1998 |title=Uses of mushrooms by Finns and Karelians |journal=International Journal of Circumpolar Health |volume=57 |issue=1 |pages=40–55 |pmid= 9567575}} However, the mushrooms are required by law to be accompanied with a warning that they are poisonous and legally prescribed preparation instructions.{{cite web| title =False morels must be accompanied by warning and handling instructions| publisher =The Finnish Food Safety Authority Evira| date =11 May 2006| url =http://www.evira.fi/portal/en/food/current_issues/?id=117| access-date =2008-03-04| archive-url =https://web.archive.org/web/20071005002432/http://www.evira.fi/portal/en/food/current_issues/?id=117| archive-date =5 October 2007| url-status =dead}} False morels are also sold prepared and canned, in which case they are ready to be used. Official figures from the Finnish Ministry of Agriculture and Forestry report a total amount of false morels sold in Finland of 21.9 tonnes in 2006 and 32.7 tonnes, noted as being above average, in 2007.{{Cite book | author =Suomen Gallup Elintarviketieto Oy | title = MARSI 2007 – Luonnonmarjojen ja -sienien kauppaantulomäärät vuonna 2007 [Amounts of wild berries and mushrooms offered for sale in 2007] | pages =10 |date=March 2007 | publisher = Finnish Ministry of Agriculture and Forestry|location=Helsinki|language=fi}} In 2002, the Finnish Food Safety Authority estimated annual consumption of false morels to be hundreds of tonnes in plentiful years.{{Cite book| title = Riskiraportti – elintarvikkeiden ja Talousveden kemialliset vaarat [Risk report on toxins in food and tapwater]| pages =38 | year =2002 | author = Finnish Food Safety Authority|language=fi}} In Finnish cuisine, false morels may be cooked in an omelette, or gently sautéed in butter in a saucepan, flour and milk added to make a béchamel sauce, or pie filling. Alternatively, more fluid can be added for a false morel soup. Typical condiments added for flavour include parsley, chives, dill and black pepper.{{cite web |url=http://www.lapinkeittiomestarit.fi/sivut/teemat/toukokuu.htm#muhennos |title=Kevät on aikaa korvasienen ja väinönputken |publisher= Lapin Keittiömestarit|access-date=22 June 2008 |archive-url=https://web.archive.org/web/20080526001334/http://www.lapinkeittiomestarit.fi/sivut/teemat/toukokuu.htm |archive-date=26 May 2008|language=fi}}{{cite book |title=North Atlantic Seafood: A Comprehensive Guide with Recipes|author=Davidson A |year=2003 |publisher=Ten Speed Press|isbn=978-1-58008-450-5 |pages=361}}

While cooking the fungus removes (most of) the toxins, the cook can become poisoned by the hydrazine fumes given off by cooking.{{cite book|last1=Miller Jr.|first1=Orson K.|title=North American Mushrooms: A Field Guide to Edible and Inedible Fungi|last2=Miller|first2=Hope H.|publisher=FalconGuides|year=2006|isbn=978-0-7627-3109-1|location=Guilford, CN|pages=509|author-link=Orson K. Miller Jr.}}

In 2015, Swedish chef {{Interlanguage link multi|Paul Svensson|sv}} caused a controversy when he prepared a dish with Gyromitra esculenta in a TV show. Mushroom expert Monica Svensson criticized him for including it, because monomethylhydrazine is a known carcinogen and there is a risk that inexperienced people might misinterpret the recipe and omit the steps that reduce the toxicity level. She also expressed criticism to Per Morberg for similar reasons. Paul Svensson said that he was not aware of the carcinogenic effects and apologized afterwards, and he promised to remove Gyromitra from his dishes.{{cite news|last1=Nilsson|first1=Kerstin|title=Här lagar tv-kocken Paul Svensson mat med giftsvamp|url=http://www.aftonbladet.se/nyheter/article20690199.ab|access-date=26 April 2015|publisher=Aftonbladet|date=26 April 2015|language=Swedish}}

Image:False morel sauce with vegetables.jpg]]

Most of the gyromitrin must be removed to render false morels edible. The recommended procedure involves either first drying and then boiling the mushrooms, or boiling the fresh mushrooms directly.{{cite web| title =False Morel Fungi – poisonous when raw | publisher = The Finnish Food Safety Authority Evira | year = 2008 | url =http://www.evira.fi/portal/en/food/information_on_food/false_morel_fungi/ | access-date = 2008-03-04| archive-url =https://web.archive.org/web/20071218205805/http://www.evira.fi/portal/en/food/information_on_food/false_morel_fungi/ | archive-date =18 December 2007}} To prepare fresh mushroom it is recommended that they are cut into small pieces and parboiled twice in copious amounts of water, at least three parts water to one part chopped mushrooms, for at least five minutes, after each boiling the mushroom should be rinsed thoroughly in clean water. Each round of parboiling reduces the free gyromitrin contents to a tenth.{{cite journal |vauthors=Pyysalo H, Niskanen A |title=On the occurrence of N-methyl-N-formylhydrazones in fresh and processed false morel, Gyromitra esculenta |journal=Journal of Agricultural and Food Chemistry |volume=25 |issue=3 |pages=644–47 |year=1977 |pmid=558239 |doi=10.1021/jf60211a006}} Significant amounts of gyromitrin are retained in the internal structure of the mushroom even after boiling. After 3 rounds of boiling for 5 minutes and discarding the water, the gyromitrin content is reduced to 6-15% of the original. After 5 rounds, this content is reduced to 7%.{{Cite book |url=https://books.google.com/books?id=AFlfpnaGu4AC&dq=info:KichABaZFzsJ:scholar.google.com/&pg=PA7 |title=Hydrazones in the False Morel |date=1995 |publisher=Nordic Council of Ministers |isbn=978-92-9120-681-0 |pages=18 |language=en}} The gyromitrin is leached into the water where it will remain, therefore the parboiling water must be discarded and replaced with fresh water after each round of boiling. However, it is still recommended that the mushroom be boiled after drying.

MMH boils at {{convert|87.5|°C|°F|sigfig=2}} and thus readily vaporizes into the air when water containing fresh false morels is boiled.{{cite journal |vauthors=Leathem AM, Dorran TJ |title=Poisoning due to raw Gyromitra esculenta (false morels) west of the Rockies |journal=Canadian Journal of Emergency Medical Care |volume=9 |issue=2 |pages=127–30 |year=2007 |pmid=17391587 |doi=10.1017/s1481803500014937|doi-access=free }} If boiling the mushrooms indoors, care should be taken to ensure adequate ventilation, and, if symptoms of monomethylhydrazine poisoning appear, immediately open all windows and move outside to seek fresh air.{{harvnb|Benjamin|1995|p=269}} Even after boiling, small amounts of gyromitrin and other hydrazine derivatives remain in the mushrooms. Given the possibility of accumulation of toxins,{{how|date=May 2023}} repeated consumption is not recommended.{{harvnb|Benjamin|1995|p=278}}

Strains with much lower concentrations of gyromitrin have been discovered, and the fungus has been successfully grown to fruiting in culture.{{cite journal |vauthors=List PH, Sundermann G |year=1974|title=Achtung! Frühjahrslorcheln |journal=Deutsche Apotheker Zeitung |volume=114 |pages=331–32}} Thus there is scope for future research into cultivation of safer strains.{{harvnb|Benjamin|1995|p=279}}

• List of deadly fungi

{{refbegin}}

; General

• {{cite book |last1=Ammirati |first1=Joseph F.|last2=Traquair |first2=James A |last3=Horgen |first3=Paul A |title=Poisonous mushrooms of the northern United States and Canada |url=https://archive.org/details/poisonousmushroo00amma |url-access=limited |year=1985 |publisher=University of Minnesota Press |location=Minneapolis |isbn=978-0-8166-1407-3 }}
• {{cite book |last=Benjamin |first= Denis R. |title=Mushrooms: poisons and panaceas—a handbook for naturalists, mycologists and physicians |url=https://archive.org/details/mushroomspoisons0000benj |url-access=registration |publisher=WH Freeman |location=New York |year=1995 |isbn=978-0-7167-2600-5}}

; Specific

{{refend}}

{{Reflist|30em|refs=

{{cite web |title=GSD Species Synonymy: Gyromitra esculenta (Pers.) Fr |url=http://www.speciesfungorum.org/GSD/GSDspecies.asp?RecordID=236690 |publisher=Species Fungorum. CAB International |access-date=2015-09-29}}

}}

{{Commons}}

• [http://botit.botany.wisc.edu/toms_fungi/may2002.html "Gyromitra esculenta, one of the false morels"]
• [http://www.mykoweb.com/CAF/species/Gyromitra_esculenta.html California Fungi—Gyromitra esculenta]
• [http://www.dlc.fi/~marianna/gourmet/morel.htm#instrc Official Finnish instructions for the processing of false morels] {{Webarchive|url=https://web.archive.org/web/20190202060538/http://www.dlc.fi/~marianna/gourmet/morel.htm#instrc |date=2 February 2019 }}

{{Taxonbar|from=Q900804}}

{{featured article}}

Category:Discinaceae

Category:Poisonous fungi

Category:Fungi of North America

Category:Fungi of Europe

Category:Fungi described in 1800

Category:Taxa named by Christiaan Hendrik Persoon

Category:Fungus species