Definitions

sponge mushroom

Morchella

Morchella, the true morels, is a genus of edible mushrooms closely related to anatomically simpler cup fungi. These distinctive mushrooms appear honeycomb-like in that the upper portion is composed of a network of ridges with pits between them. These ascocarps are prized by gourmet cooks, particularly for French cuisine. Commercial value aside, morels are hunted by thousands of people every year simply for their taste and the joy of the hunt. Morels have been called by many local names; some of the more colorful include dryland fish, due to their similarity in taste to fish, or hickory chickens, as they are known in many parts of Kentucky; and "merkels" or "miracles," based on a story of how a mountain family was saved from starvation by eating morels.

Location of morels

The morel grows abundantly in the two and sometimes three years immediately following a forest fire. However, where fire suppression is practiced, they may grow regularly in small amounts in the same spot year after year. Commercial pickers and buyers in North America will follow forest fires to gather morels. The Finnish name, huhtasieni, refers to huhta, area cleared for agriculture by slash and burn method. These spots may be jealously guarded by mushroom pickers, as the mushrooms are a delicacy and sometimes a cash crop. Although no symbiotic relationships have been proven between morels and certain tree species, experienced morel hunters swear by these relationships. Trees commonly associated with morels include ash, sycamore, tulip tree, dead and dying elms, cottonwoods and old apple trees (remnants of orchards). However, they are more commonly found under deciduous trees rather than conifers. Morels have not yet been successfully farmed on a large scale, and the commercial morel industry is largely based on harvest of wild mushrooms.

Cooking

Morels are a feature of many cuisines, including Provençal. Though morels are typically sold dried or canned, they can be purchased fresh. When preparing fresh morels for consumption, soaking them may ruin their delicate flavor. Due to their natural porousness, morels may contain trace amounts of soil which cannot be washed out. One of the best and simplest ways to enjoy morels is by gently sauteeing them in butter, cracking pepper on top and sprinkling a bit of salt on.

Types of morel mushrooms

The best known morels are the Yellow Morel or Common Morel (Morchella esculenta); the White Morel (M. deliciosa); and the Black Morel (M. elata). Other common names for morels include Merkel, Sponge Mushroom and Molly Moocher. In the Appalachian mountains in Tennessee, Southwestern Virginia and Kentucky they are known as dry land fish and hickory chickens. When gathering morels, care must be taken to distinguish them from the poisonous false morel (Gyromitra esculenta and others). Other species of true morels include M. semilibera and M. vulgaris. Discriminating between the various species is complicated by uncertainty regarding which species are truly biologically distinct. Mushroom hunters refer to them by their color (e.g., gray, yellow, black) as the species are very similar in appearance and vary considerably within species and age of individual.

Toxicity

Morels contain small amounts of toxins that are usually removed by thorough cooking; morel mushrooms should never be eaten raw. It has been reported that even cooked morels can sometimes cause mild poisoning symptoms when consumed with alcohol.

Genus Morchella is derived from "morchel", an old German word for mushroom. There are about a dozen different kinds of morels but they seem to cross, making exact identification very hard without a microscope. It is important to try small amounts of any edible mushroom, and only eat ones that are clean and free of decay.

Early Morels

Verpa Bohemica are also called wrinkled thimble cap, or early morel, and Ptychoverpa Bohemica. Although the early false morels are sometimes eaten without ill effect, they can cause severe gastrointestinal upset and loss of muscular coordination (including cardiac muscle) if eaten in large quantities or over several days in a row. They should be parboiled and dried before use in cooking to break down a gyromitrin-like toxin (an organic, carcinogenic poison) that is produced by the mushroom.

The early false morels can be told apart from the true morels by careful study of how the cap is attached to the stalk. The edge of true morels' (morchella) caps are intergrown with the stalk, but early morels' (verpas) caps hang over like a thimble, for which they are sometimes referred to as "thimble morel". Early false morels are the first morels to fruit in the spring, shortly after leaves begin to form on deciduous trees. Narrow-head morels (morchella angusticeps) fruit next, around May. The last morels to fruit are the yellow or white morels (Morchella esculenta), then crassipes.

Cap: the cap of false morels is wrinkled and irregular, bell shaped or cone shaped, attached only at apex (top) of cap not like true morels which have caps that are attached at the bottom, the color yellow brown to olive yellow or tan, darkens with age.

Stalk: 6-16cm high, white to creamy or tan, hollow, often stuffed with white cottony pith. Spores when seen under a microscope are elliptical and have large oil droplets; true morels have no oil droplets.

Gyromitra false morel

Helvellaceae is a family of fungi, also called false morels or brain mushrooms because of their irregularly shaped heads or caps. Helvella is Latin for small vegetable. Gyromitra is a genus in this family which contains species with heads and stalks. Gyromitra species are medium to large sized saprophytic fungi that grow on ground or on rotten wood.

Cap: irregularly lobed, wrinkled and brain shaped, sometimes saddle shaped; outside is some shade of brown from purplish to reddish or olive brown; the inside is often filled with hollow chambers; the margin (edge) may or may not be attached to the stalk.

Stalk: usually paler than cap, round and smooth or ribbed, inside chambered, folded or hollow, fragile.

Edibility: Gyromitras are deadly raw or improperly prepared. False morels (Gyromitra species) are eaten by many people and G. esculenta is also called brain mushroom, beefsteak morel, lorchel edible fake morel and conifer false morel, and sold in markets especially in Europe, but this fungus (G. esculenta and other species in this genus) have definitely caused many deaths, especially in Europe. In North America M.E. Schalkwijk-Barendsen 1991 states that an Edmonton boy was in a coma for 18 hours in hospital after nibbling on a raw G. esculenta. The reaction came 8 hours after and left him with liver damage. His mother was also very ill from the cooking fumes. She also said that G. esculenta has caused many deaths in Europe and eastern North America. The Western strain does not seem to contain as much Gyromitrin (a poison named after Gyromitra). This poison has a strong dissolving action on red blood corpuscles, damages the liver and is carcinogenic.

Some people are allergic (idiosyncratic or hypersensitive) to these fungi.

The toxin Gyromitrin, a protoplasmic poison: species which contain this poison are Gyromitra esculenta, G. gigas, G. fastigiata (G. brunnea), G. infula and some others.

Chemically, Gyromitrins are derivatives of N-methyl-N-formylhydrazine (MFH), which is released into the body and then oxidized to produce the extremely poisonous N-nitroso-N-methylformamide (NMFA). False morels can be rendered edible by parboiling and discarding the water at least twice or by long drying; both of these procedures destroy more than 99% of the hydrazine content in these fungi according to Varro E. Tyler 1962-1987. He also said that unpublished studies carried out at Purdue University show that European specimens contain nearly 10 times as much Gyromitrin as similar specimens collected in the Puget Sound area. Obviously different strains of these fungi exist with different amounts of poison. Only an occasional case of poisoning has been reported from samples collected west of the Rocky Mountains but NMFA, the active principle derived from Gyromitrin, has been shown to be highly carcinogenic in small animals.

Call a physician in any case of poisoning or suspected poisoning. Treatment involves intravenous administration of large amounts of pyridoxine hydrochloride.

Symptoms appear from 2-8 hours after the meal, sometimes up to 20. Symptoms begin with a feeling of fullness followed by violent vomiting and watery diarrhea which may persist for one or two days. Headache, lassitude, cramps, and intense pain in the liver and gastric region followed by jaundice. In severe cases, the patient undergoes general collapse, the pulse becomes irregular, breathing is difficult and delirium and convulsions occur. Death occurs in 15-35% of cases from liver damage or heart failure, usually within 7 days.

Gyromitrin poisoning has puzzled scientists for many years because of the very narrow threshold between complete absence of discomfort and severe poisoning or death. Gyromitrin's product of hydrolysis, Monomethydrazine CH3N2H3 (MMH), is a very poisonous compound used in the manufacture of rocket fuel.

Small amounts of this poison is said to occur in the Agaricus bisporus (A. brunnescens and A. hortensis, the brown and white varieties), the common button mushroom sold in the grocery stores. This poison is said to be highly carcinogenic; thus it would not be safe to eat MMH-containing mushrooms even after parboiling or drying.

See also

References

External links

Further reading

  • Harvesting Morels After Wildfire in Alaska. Wurtz et al. USDA Forest Service Research Note PNW-RN-546, February 2005

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