Gyromitra Esculenta

''Gyromitra esculenta'' is an ascomycete fungus from the genus '' Gyromitra'', widely distributed across Europe and North America. It normally fruits in sandy soils under coniferous trees in spring and early summer. The fruiting body, or mushroom, is an irregular brain-shaped cap dark brown in colour that can reach high and wide, perched on a stout white stipe up to high.

Although potentially fatal if eaten raw, ''Gyromitra esculenta'' is a popular delicacy in Scandinavia, Eastern Europe, and the upper Great Lakes region of North America. Although popular in some districts of the eastern Pyrenees, it is prohibited from sale to the public in Spain. It may be sold fresh in Finland, but it must be accompanied by warnings and instructions on correct preparation.

Although it is still commonly parboiled before preparation, evidence suggests that even this procedure may not make ''Gyromitra esculenta'' entirely safe for consumption. When consumed, the principal active agent, gyromitrin, is hydrolyzed into the toxic compound monomethylhydrazine (MMH), a type of rocket fuel. The toxin affects the liver, central nervous system, and sometimes the kidneys. Symptoms of poisoning involve vomiting and diarrhea several hours after consumption, followed by dizziness, lethargy and headache. Severe cases may lead to delirium, coma and death after five to seven days.

Taxonomy and naming

The fungus was first described in 1800, by mycologist Christian Hendrik Persoon, as ''Helvella esculenta'', and gained its current accepted binomial name when the Swedish mycologist Elias Magnus Fries placed it in the genus ''Gyromitra'' in 1849. The genus name is derived from the Greek terms ''gyros''/γυρος "round" and ''mitra''/μιτρα "headband". Its specific epithet is derived from the Latin ''esculentus'', "edible".

It is known by a variety of common descriptive names such as "brain mushroom", "turban fungus", ''elephant ears'', or "beefsteak mushroom/morel", although ''beefsteak mushroom'' can also refer to the much less toxic basidiomycete '' Fistulina hepatica''. Dating from the 19th century, the German term is a result of the older , itself from the 18th century Low German , aligning with the similar-sounding (and similar-looking) .

''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. The toxic qualities of ''G. esculenta'' may be reduced by cooking, but possibly not enough to prevent poisoning from repeated consumption.

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.

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 ''Gyromitra 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.

Description

Resembling a brain, the irregularly shaped cap may be up to high and 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. Specimens from California may have more reddish-brown caps. Attached to the cap at several points, the stipe is high and wide. ''Gyromitra 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.

Similar species

''Gyromitra 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.

''Gyromitra gigas'', ''G. infula'' and '' G. ambigua'' in particular are similar. The latter two are toxic to humans.

Distribution and habitat

''Gyromitra 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 aspen (''Populus