Mushrooms

views updated May 21 2018

Mushrooms

Biology and Ecology of Mushroom-Producing Fungi

Mushrooms of North America

Poisonous Mushrooms and Drugs

Edible Mushrooms

A Warning

Resources

Mushrooms are the fruiting bodies of certain species of higher fungi. The vegetative tissues of these fungi consists of immense lengths of microscopic, thread-like hyphae, and their aggregations known as mycelium, which grow in surface soils, organic debris, and in association with plant roots.

Strictly speaking, a mushroom is the sporulating or fruiting body of a fungus in the division Basidiomycetes, a large and diverse group of about 16,000 species, sometimes known as club fungi. Species of Basidiomycetes can be saprophytic, parasitic, or mycorrhizal in their ecology. Because of the relative complexity of their anatomy and breeding systems, the Basidiomycetes are considered to be the most evolutionarily advanced of the fungi. The mushrooms of these fungi are technically known as basidiocarps. These structures are formed of specialized mycelium, and are the spore-producing stage of development. The basidiocarp is a relatively short-lived stage of the life cycle, most of which is spent living as microscopic, thread like hyphae, which ramify extensively through the growth substrate of the fungus.

However, in its common usage, the word mushroom is also used to refer to the spore-producing bodies of other types of fungi, in particular a few species in the division Ascomycetes or sac fungi, which includes the familiar, edible morels and truffles. Some of the non-Basidiomycetes species that develop mushrooms are also discussed in this entry.

Mushrooms have long been avidly sought-after as a tasty country food in many cultures, although some peoples, notably the Anglo-Saxons of Britain, have tended to disdain these foods. This has not been because of the flavor of mushrooms, but rather because some species are deadly poisonous, and these are not always easily distinguished from nontoxic and therefore edible species.

The mycophobia (that is, fear of fungus) common to some people and cultures can be illustrated in many ways, including the derivation of the word toadstool, a commonly used name for mushrooms that have an erect stalk and a wide cap. Tod is the German word for death, and the deadly, poisonous nature of certain mushrooms may be the likely origin of the word toadstool. The etymology of toadstool is further compounded by the poisonous nature of toads. In any event, European folk tales refer to toadstools as places where poisonous toads sit on poisonous mushrooms in the forest, a myth perpetuated in whimsical drawings accompanying fairy tales and other stories intended for children.

Mushrooms have many fascinating properties, in addition to the extreme toxicity of some species. Mushrooms can sometimes grow extremely rapidlyin some cases, masses of mushrooms can seemingly appear overnight, under suitable environmental conditions, and usually following a heavy rainfall. Mushrooms may also have unusual shapes and growth patterns, for example, the concentric circles or fairy rings that some species develop in open places, such as fields and meadows. These and other interesting qualities were not easily explainable by naturalists in earlier times. As a result, mushrooms have acquired a supernatural reputation in some cultures, and are commonly associated with cold, dank, dangerous, or evil contexts. Many cultures have similarly regarded a few other creatures, such as snakes, bats, and spiders. Today, however, these various cultural prejudices are much less prevalent, because we have a greater scientific understanding of the biology and ecology of mushrooms and other unusual organisms.

Biology and Ecology of Mushroom-Producing Fungi

As was just noted, mushrooms are the fruiting bodies of certain types of fungi. Most of the biomass of these fungi consists of fine, thread like hyphae, which grow extensively throughout the organic-rich substrate of their ecosystem. These fungi periodically develop spore-producing, reproductive structures known as mushrooms, under conditions of a favorable environment in terms of temperature and moisture, coupled with the accumulation of sufficient energy and nutrient reserves to support the reproductive effort. It may take years for these favorable circumstances to develop, and consequently mushroom populations in forests, prairies, fields, and other habitats can be highly variable in abundance.

Species of mushroom-producing fungi exploit various types of microhabitats. The most important of these are the surface soil and organic litter, large-dimension woody debris, mycorrhizae, and animal dung. These are discussed below:

(1) The hyphae of many species of fungus grow extensively through the soil and surface organic matter, such as the forest floor and the organic mat of prairies and savannas. These hyphae are the vegetative tissues of saprophytic fungi, which are an important component of the decomposer food web of their ecosystem.

(2) Many other species of fungi are saprophytes that grow in decaying wood, such as logs and branches lying on the forest floor, standing dead trees (these are known as snags), and rotting heartwood of living trees. Some of these fungi become significant economic pests, for example, by causing dry-rot of the wooden components of buildings.

(3) Many species of fungus grow in a close association with the roots of higher plants, in a mutualistic symbiosis known as a mycorrhiza. The mycorrhizal mutualism is very important to the nutrition of the plant, because of the greatly enhanced access to nutrients that is provided, particularly to phosphate.

(4) An additional habitat that may be exploited by mushroom-producing fungi includes piles of animal dung, especially the organic-rich manure of herbivores. These are known as coprophilous fungi.

Mushrooms of North America

Many species of mushrooms occur in the forests, prairies, fields, and towns and cities of North America. Obviously, it is not possible to deal with these in a comprehensive fashion. Some of the more widespread of the stranger species are briefly described here, while poisonous and edible ones are discussed in the following sections.

The largest mushroom to occur in North America are the giant puffballs (Calvatia gigantea and C. booniana ). These species develop huge, ball-like mushrooms that can achieve a diameter of up to 19.5 in (50 cm).

The stinkhorn fungus (Phallus inpudicus ) is a saprophyte that grows up out of the forest floor. This species is also sometimes known as the dogs-penis or devils-penis, because of the anatomically-correct shape of the mushroom, and in the case of the latter name, its terrible smell.

The artists fungus (Ganoderma applanatum ) is a large, semi-circular, relatively hard and corky mushroom that grows bracket-like out of the side of heartrotted trees. The white surface of this fungus turns a darker brown when it is bruised. Consequently, the smooth, lower surface of the mushroom is sometimes used as a substrate to record messages and make drawings. The related sulphur shelf (Laetiporus sulphureus ) also grows out of the side of heart-rotted trees, and is a bright yellow in color.

The scarlet elf cup (Sarcoscypha coccinea ) is a lovely mushroom, with a deeply concave cup, that is white on the exterior, and a brilliant scarlet on the interior. This species occurs on rotting sticks and small logs in forests in the springtime.

The white worm coral (Clavaria vermicularis ) occurs in clusters of erect, white, worm like clubs growing out of the forest floor, and is found during the summer and autumn.

The collared earthstar (Geastrum triplex ) grows out of the forest floor. This species has a bulbous spore-case, surrounded by pointed, ray like structures that gives an overall appearance of a star-burst.

Poisonous Mushrooms and Drugs

Some species of mycorrhizal fungi develop mushrooms that are deadly poisonous. Perhaps the most famous, and most-rapidly killing species in this respect are the death or destroying angel (Amanita virosa ) and the deathcap (A. palloides ). There are other species of deadly mushrooms in the genus Amanita, and in the genera Chlorophyllum (green gill), Cortinarius (web-caps), Galerina (autumn skullcaps), Gyromitra (false morels), and Lepiota (parasol mushrooms). However, these are not, by any means, the only poisonous mushrooms that may be commonly encountered in wild habitats in North America. There are numerous other species of deadly mushrooms, which are never to be eaten.

A number of fungi are used as drugs, to induce hallucinations, feelings of well-being, and other pleasurable mental states. The fly agaric (Amanita muscaria ) is a widespread species of Eurasia, North America, and Central America, and is a well-known poisonous mushroom. However, in smaller doses this species can induce pleasant intoxication and hallucinations, and it has long been used by many cultures to induce these effects. This has been the case in Siberia, elsewhere in northeastern Asia, Central Asia, and India, where the drug is known by the indigenous name soma. The fly agaric has also been used in northwestern Europe, where Viking warriors sometimes consumed this drug prior to battle and certain ceremonies, and were known as berserkers, and in Central America, where the fungus was considered to be a food from the gods. In the famous childrens story, Alice in Wonderland, Alice could change her size from very small to very large, by nibbling on a mushroom. This tale was undoubtedly influenced by the authors knowledge of the hallucinogenic properties of Amanita muscaria. It is well-known that prolonged or frequent use of this hallucinogen is damaging to the nervous system, and that large doses can be lethal, but this mushroom has nevertheless been important in many cultures, and is still routinely used for certain types of ceremonies.

Various species of American mushrooms known as psilocybin (Psilocybe spp.) are also hallucinogenic. These were used in religious ceremonies by some Amerindian cultures, for example, the Aztecs, who knew these mushrooms as teonanacatyl (especially using P. mexicana ). However, these mushrooms are mostly used today as recreational drugs. Other mushroom-producing fungi that contain the same active ingredient, known as psilocybin, are species in the genera Conocybe, Paneolus, Psathyrella, and Stropharia.

A therapeutic drug is manufactured from the fruiting bodies of the ergot (Claviceps purpurea ), which is a parasite on the flowering heads of certain grasses, especially rye (Secale cereale ). The ergot fungus attacks the young fruits of the grasses, and then develops a bulbous, purplish structure. These are collected and used to make a medicine useful in treating low bloodpressure, hemorrhages, and other maladies.

Edible Mushrooms

The use of wild mushrooms as a food is an ancient practice. These fungi were undoubtedly well known to pre-historic, hunting and gathering cultures, as they are today to indigenous peoples who continue to live in natural forests. Once the identity of poisonous and edible mushrooms became fixed in cultural knowledge and tradition, the edible species, and sometimes those that could be used to induce non-lethal hallucinogens, were regularly gathered and utilized by people.

The tradition of the use of mushrooms as a country food continues today. The collection of edible mushrooms is an especially popular outdoor activity in much of Eurasia, where these foods can be very common in the spring and autumn in boreal and temperate forests. Mushroom collecting has been considerably less popular in Britain and North America. However, under the influence of immigrants from Europe and northern Asia, and the emerging popularity of natural history, more and more North Americans are actively seeking out these delicacies in wild habitats. This activity has been called mushrooming, in parallel with the better-known sport of birding. Interestingly, most mushrooms are not a particularly nutritious food. They typically contain 90-95% water when fresh, the rest of their biomass being about 5% carbohydrate, 5% protein, and less-than 1% fat and minerals. The major benefit of eating mushrooms is their engaging, sometimes exquisite flavor, and in some cases their interesting texture.

The truffles are perhaps the most famous, and certainly the most expensive, of the edible mushrooms, being avidly sought-out for use in gourmet cooking, particularly in France. The best-known species of truffle is Tuber melanosporum, which is commonly mycorrhizal on species of oak, birch, and beech (Quercus, Betula, and Fagus spp., respectively). Other Eurasian species of truffle include Tuber aestivum and T. brumale, while T. gibbosum occurs in conifer rainforests of the west coast of North America. The spore-bearing mushrooms of truffles develop underground, and are commonly discovered using a specially trained, truffle-sniffing pig or dog.

The chanterelle (Cantharellus cibarius ) is a yellow-to-orange mushroom of the floor of autumn forests, and is a delicious wild fungus. The king bolete (Boletus edulis ) is another prized mushroom. The shaggy mane (Coprinus comatus ) is delicious if picked when young. Puffballs can also be eaten, as long as their interior is still young and white-colored, and include the pear puffball (Lycoperdon pyriforme ) and giantpuffball(Calvatia gigantea ). Other edible mushrooms include corn smut (Ustilago maydis ), beefsteak (Fistulina hepatica ), fried chicken mushroom (Lyophyllum decastes ), fairy ring mushroom (Marasmius oreades ), oyster fungus (Pleurotus ostreatus ), and the morel (Morchella esculenta ).

Some species of mushrooms have been brought into domestication, and are routinely grown on artificial media, to be harvested and sold as an agricultural product. Mushroom cultivation appears to have begun in England in the late eighteenth century, and it has become a major economic enterprise because of the rapidly increasing popularity of mushrooms as food.

The most commonly cultivated species of mushroom is the common meadow mushroom (Agaricus campestris ; sometimes known as A. bisporus ), which sustains a global economy exceeding $15 billion per year. This mushroom can be eaten fresh or dried for longer-term storage. This species is cultivated using an organic-rich medium, with the straw- and manure-rich cleanings of horse stables being a preferred material. The substrate must be sterilized, usually by a natural, high-temperature composting referred to as

KEY TERMS

Hypha (plural, hyphae) Cellular unit of a fungus, typically a branched and tubular filament. Many strands (hyphae) together are called mycelium.

Mutualism An intimate relationship between two or more organisms that is beneficial to both.

Mycelium This refers to thread or matlike aggregations of the fine fungal tissues known as hyphae.

Saprophyte This refers to an organism that derives its energy by decomposing dead organic matter. Many species of mushroom-producing fungi live off the organic debris that is present in the mineral soil and, especially, the surface litter of leaves and woody debris on the forest floor.

sweating-out. This must be done before the substrate is inoculated with the Agaricus, to prevent the growth of other species of fungus, which may be pathogenic or more competitive than the desired species. The substrate is typically inoculated with spawn, that is, masses of mycelium compressed into small briquettes, or with a laboratory culture of the Agaricus. The growth conditions should be dark or virtually so, as humid as possible, and the temperature kept constant at about 5559°F (1315°C). Mushroom farms may be developed in specially constructed, barn like buildings, or in caves, worked-out mines, and cellars. Typically, the first mushroom buttons begin to appear about four weeks after inoculation and growth and proliferation of the Agaricus mycelium, and the first harvests can be made after 7-8 weeks. The mushrooms can be continuously harvested for 4-6 months, after which the growth medium is considered to be spent. However, this well-composted substrate can then be used as an excellent soil conditioner in gardens.

Other species of mushrooms are also cultivated, including the shiitake (Cortinellus berkeleyanus ), a popular ingredient in oriental cooking. The shiitake mushroom is cultivated on rotting logs and is typically dried for storage.

A Warning

Many people get great pleasure out of collecting and eating wild mushrooms. Many of the tastiest species are quite distinctive in shape and color and can be collected and eaten without any risk and with great pleasure. However, some species of edible mushrooms are rather similar to species that are deadly poisonous. When collecting wild mushrooms as food, it is always best to err on the side of certainty of identification and safety. The identification of some types of mushrooms is difficult, and there are no hard-and-fast rules for separating poisonous from edible species. This is the reason why there are numerous stories about experienced mushroom collectors who were poisoned by eating a misidentified fungus. Therefore, if you are not certain about the identity of a particular wild mushroom, do not consume it. Eating a poisonous mushroom can quickly lead to liver failure and death.

See also Fungicide.

Resources

BOOKS

Lincoff, G.H. The Audubon Society Field Guide to North American Mushrooms. New York: Chanticleer Press, 1981.

McKnight, K.H., and V.B. McKnight. A Field Guide to the Mushrooms of North America. Boston: Houghton Mifflin Co., 1987.

Bill Freedman

Mushrooms

views updated May 21 2018

Mushrooms

Mushrooms are the fruiting bodies of certain species of higher fungi . The vegetative tissues of these fungi consists of immense lengths of microscopic, thread-like hyphae, and their aggregations known as mycelium, which grow in surface soils, organic debris, and in association with plant roots.

Strictly speaking, a mushroom is the sporulating or fruiting body of a fungus in the division Basidiomycetes, a large and diverse group of about 16,000 species, sometimes known as club fungi. Species of Basidiomycetes can be saprophytic, parasitic, or mycorrhizal in their ecology . Because of the relative complexity of their anatomy and breeding systems, the Basidiomycetes are considered to be the most evolutionarily advanced of the fungi. The mushrooms of these fungi are technically known as basidiocarps. These structures are formed of specialized mycelium, and are the spore-producing stage of development. The basidiocarp is a relatively short-lived stage of the life cycle, most of which is spent living as microscopic, thread-like hyphae, which ramify extensively through the growth substrate of the fungus.

However, in its common usage, the word mushroom is also used to refer to the spore-producing bodies of other types of fungi, in particular a few species in the division Ascomycetes or sac fungi, which includes the familiar, edible morels and truffles. Some of the non-Basidiomycetes species that develop "mushrooms" are also discussed in this entry.

Mushrooms have long been avidly sought-after as a tasty country food in many cultures, although some peoples, notably the Anglo-Saxons of Britain, have tended to disdain these foods. This has not been because of the flavor of mushrooms, but rather because some species are deadly poisonous, and these are not always easily distinguished from nontoxic and therefore edible species.

The mycophobia (that is, fear of fungus) common to some people and cultures can be illustrated in many ways, including the derivation of the word "toadstool," a commonly used name for mushrooms that have an erect stalk and a wide cap. "Tod" is the German word for death, and the deadly, poisonous nature of certain mushrooms may be the likely origin of the word toadstool. The etymology of toadstool is further compounded by the poisonous nature of toads . In any event, European folk tales refer to toadstools as places where poisonous toads sit on poisonous mushrooms in the forest, a myth perpetuated in whimsical drawings accompanying fairy tales and other stories intended for children.

Mushrooms have many fascinating properties, in addition to the extreme toxicity of some species. Mushrooms can sometimes grow extremely rapidly—in some cases, masses of mushrooms can seemingly appear overnight, under suitable environmental conditions, and usually following a heavy rainfall. Mushrooms may also have unusual shapes and growth patterns, for example, the concentric circles or "fairy rings" that some species develop in open places, such as fields and meadows. These and other interesting qualities were not easily explainable by naturalists in earlier times. As a result, mushrooms have acquired a supernatural reputation in some cultures, and are commonly associated with cold, dank, dangerous, or evil contexts. Many cultures have similarly regarded a few other creatures, such as snakes , bats , and spiders. Today, however, these various cultural prejudices are much less prevalent, because we have a greater scientific understanding of the biology and ecology of mushrooms and other unusual organisms.


Biology and ecology of mushroom-producing fungi

As was just noted, mushrooms are the fruiting bodies of certain types of fungi. Most of the biomass of these fungi consists of fine, thread-like hyphae, which grow extensively throughout the organic-rich substrate of their ecosystem . These fungi periodically develop spore-producing, reproductive structures known as mushrooms, under conditions of a favorable environment in terms of temperature and moisture, coupled with the accumulation of sufficient energy and nutrient reserves to support the reproductive effort. It may take years for these favorable circumstances to develop, and consequently mushroom populations in forests , prairies, fields, and other habitats can be highly variable in abundance.

Species of mushroom-producing fungi exploit various types of microhabitats. The most important of these are the surface soil and organic litter, large-dimension woody debris, mycorrhizae, and animal dung. These are discussed below:

  1. The hyphae of many species of fungus grow extensively through the soil and surface organic matter , such as the forest floor and the organic mat of prairies and savannas. These hyphae are the vegetative tissues of saprophytic fungi, which are an important component of the decomposer food web of their ecosystem.
  2. Many other species of fungi are saprophytes that grow in decaying wood , such as logs and branches lying on the forest floor, standing dead trees (these are known as "snags"), and rotting heartwood of living trees. Some of these fungi become significant economic "pests," for example, by causing dry-rot of the wooden components of buildings.
  3. Many species of fungus grow in a close association with the roots of higher plants, in a mutualistic symbiosis known as a mycorrhiza . The mycorrhizal mutualism is very important to the nutrition of the plant, because of the greatly enhanced access to nutrients that is provided, particularly to phosphate.
  4. An additional habitat that may be exploited by mushroom-producing fungi includes piles of animal dung, especially the organic-rich manure of herbivores. These are known as coprophilous fungi.

Mushrooms of North America

Many species of mushrooms occur in the forests, prairies, fields, and towns and cities of North America . Obviously, it is not possible to deal with these in a comprehensive fashion. Some of the more widespread of the stranger species are briefly described here, while poisonous and edible ones are discussed in the following sections.

The largest mushroom to occur in North America is the giant puffball (Calvatia gigantea and C. booniana). These species develop huge, ball-like mushrooms that can achieve a diameter of up to 19.5 in (50 cm).

The stinkhorn fungus (Phallus inpudicus) is a saprophyte that grows up out of the forest floor. This species is also sometimes known as the dog's-penis or devil's-penis, because of the anatomically-correct shape of the mushroom, and in the case of the latter name, it's terrible smell.

The artist's fungus (Ganoderma applanatum) is a large, semi-circular, relatively hard and corky mushroom that grows bracket-like out of the side of heart-rotted trees. The white surface of this fungus turns a darker brown when it is bruised. Consequently, the smooth, lower surface of the mushroom is sometimes used as a substrate to record messages and make drawings. The related sulphur shelf (Laetiporus sulphureus) also grows out of the side of heart-rotted trees, and is a bright yellow in color .

The scarlet elf cup (Sarcoscypha coccinea) is a lovely mushroom, with a deeply concave cup, that is white on the exterior, and a brilliant scarlet on the interior. This species occurs on rotting sticks and small logs in forests in the springtime.

The white worm coral (Clavaria vermicularis) occurs in clusters of erect, white, worm-like clubs growing out of the forest floor, and is found during the summer and autumn.

The collared earthstar (Geastrum triplex) grows out of the forest floor. This species has a bulbous spore-case, surrounded by pointed, ray-like structures that gives an overall appearance of a star-burst.


Poisonous mushrooms and drugs

Some species of mycorrhizal fungi develop mushrooms that are deadly poisonous. Perhaps the most famous, and most-rapidly killing species in this respect are the death or destroying angel (Amanita virosa) and the deathcap (A. palloides). There are other species of deadly mushrooms in the genus Amanita, and in the genera Chlorophyllum (green gill), Cortinarius (webcaps), Galerina (autumn skullcaps), Gyromitra (false morels), and Lepiota (parasol mushrooms). However, these are not, by any means, the only poisonous mushrooms that may be commonly encountered in wild habitats in North America. There are numerous other species of deadly mushrooms, which are never to be eaten.

A number of fungi are used as drugs, to induce hallucinations, feelings of well-being, and other pleasurable mental states. The fly agaric (Amanita muscaria) is a widespread species of Eurasia, North America, and Central America, and is a well-known poisonous mushroom. However, in smaller doses this species can induce pleasant intoxication and hallucinations, and it has long been used by many cultures to induce these effects. This has been the case in Siberia, elsewhere in northeastern Asia , Central Asia, and India, where the drug is known by the indigenous name "soma." The fly agaric has also been used in northwestern Europe , where Viking warriors sometimes consumed this drug prior to battle and certain ceremonies, and were known as "berserkers," and in Central America, where the fungus was considered to be a food from the gods. In the famous children's story, Alice in Wonderland, Alice could change her size from very small to very large, by nibbling on a mushroom. This tale was undoubtedly influenced by the author's knowledge of the hallucinogenic properties of Amanita muscaria. It is well-known that prolonged or frequent use of this hallucinogen is damaging to the nervous system , and that large doses can be lethal, but this mushroom has nevertheless been important in many cultures, and is still routinely used for certain types of ceremonies.

Various species of American mushrooms known as psilocybin (Psilocybe spp.) are also hallucinogenic. These were used in religious ceremonies by some Amerindian cultures, for example, the Aztecs, who knew these mushrooms as teonanacatyl (especially using P. mexicana). However, these mushrooms are mostly used today as recreational drugs. Other mushroom-producing fungi that contain the same active ingredient, known as psilocybin, are species in the genera Conocybe, Paneolus, Psathyrella, and Stropharia.

A therapeutic drug is manufactured from the fruiting bodies of the ergot (Claviceps purpurea), which is a parasite on the flowering heads of certain grasses , especially rye (Secale cereale). The ergot fungus attacks the young fruits of the grasses, and then develops a bulbous, purplish structure. These are collected and used to make a medicine useful in treating low blood pressure , hemorrhages, and other maladies.


Edible mushrooms

The use of wild mushrooms as a food is an ancient practice. These fungi were undoubtedly well known to pre-historic, hunting and gathering cultures, as they are today to indigenous peoples who continue to live in natural forests. Once the identity of poisonous and edible mushrooms became fixed in cultural knowledge and tradition, the edible species, and sometimes those that could be used to induce non-lethal hallucinogens , were regularly gathered and utilized by people.

The tradition of the use of mushrooms as a country food continues today. The collection of edible mushrooms is an especially popular outdoor activity in much of Eurasia, where these foods can be very common in the spring and autumn in boreal and temperate forests. Mushroom collecting has been considerably less popular in Britain and North America. However, under the influence of immigrants from Europe and northern Asia, and the emerging popularity of natural history, more and more North Americans are actively seeking out these delicacies in wild habitats. This activity has been called "mushrooming," in parallel with the better-known sport of "birding." Interestingly, most mushrooms are not a particularly nutritious food. They typically contain 90-95% water when fresh, the rest of their biomass being about 5% carbohydrate , 5% protein, and less-than 1% fat and minerals . The major benefit of eating mushrooms is their engaging, sometimes exquisite flavor, and in some cases their interesting texture.

The truffles are perhaps the most famous, and certainly the most expensive, of the edible mushrooms, being avidly sought-out for use in gourmet cooking, particularly in France. The best-known species of truffle is Tuber melanosporum, which is commonly mycorrhizal on species of oak, birch, and beech (Quercus, Betula, and Fagus spp., respectively). Other Eurasian species of truffle include Tuber aestivum and T. brumale, while T.gibbosum occurs in conifer rainforests of the west coast of North America. The spore-bearing mushrooms of truffles develop underground, and are commonly discovered using a specially trained, truffle-sniffing pig or dog.

The chanterelle (Cantharellus cibarius) is a yellow-to-orange mushroom of the floor of autumn forests, and is a delicious wild fungus. The king bolete (Boletus edulis) is another prized mushroom. The shaggy mane (Coprinus comatus) is delicious if picked when young. Puffballs can also be eaten, as long as their interior is still young and white-colored, and include the pear puffball (Lycoperdon pyriforme) and giant puffball (Calvatia gigantea). Other edible mushrooms include corn smut (Ustilago maydis), beefsteak (Fistulina hepatica), fried chicken mushroom (Lyophyllum decastes), fairy ring mushroom (Marasmius oreades), oyster fungus (Pleurotus ostreatus), and the morel (Morchella esculenta).

Some species of mushrooms have been brought into domestication, and are routinely grown on artificial media, to be harvested and sold as an agricultural product. Mushroom cultivation appears to have begun in England in the late eighteenth century, and it has become a major economic enterprise because of the rapidly increasing popularity of mushrooms as food.

The most commonly cultivated species of mushroom is the common meadow mushroom (Agaricus campestris; sometimes known as A. bisporus), which sustains a global economy exceeding $15 billion per year. This mushroom can be eaten fresh or dried for longer-term storage. This species is cultivated using an organic-rich medium, with the straw- and manure-rich cleanings of horse stables being a preferred material. The substrate must be sterilized, usually by a natural, high-temperature composting referred to as "sweating-out." This must be done before the substrate is inoculated with the Agaricus, to prevent the growth of other species of fungus, which may be pathogenic or more competitive than the desired species. The substrate is typically inoculated with "spawn," that is, masses of mycelium compressed into small briquettes, or with a laboratory culture of the Agaricus. The growth conditions should be dark or virtually so, as humid as possible, and the temperature kept constant at about 55–59°F (13–15°C). Mushroom farms may be developed in specially constructed, barn-like buildings, or in caves, worked-out mines, and cellars. Typically, the first mushroom "buttons" begin to appear about four weeks after inoculation and growth and proliferation of the Agaricus mycelium, and the first harvests can be made after 7-8 weeks. The mushrooms can be continuously harvested for 4-6 months, after which the growth medium is considered to be "spent." However, this well-composted substrate can then be used as an excellent soil conditioner in gardens.

Other species of mushrooms are also cultivated, including the shiitake (Cortinellus berkeleyanus), a popular ingredient in oriental cooking. The shiitake mushroom is cultivated on rotting logs and is typically dried for storage.


A warning

Many people get great pleasure out of collecting and eating wild mushrooms. Many of the tastiest species are quite distinctive in shape and color and can be collected and eaten without any risk and with great pleasure. However, some species of edible mushrooms are rather similar to species that are deadly poisonous. When collecting wild mushrooms as food, it is always best to err on the side of certainty of identification and safety. The identification of some types of mushrooms is difficult, and there are no hard-and-fast rules for separating poisonous from edible species. This is the reason why there are numerous stories about experienced mushroom collectors who were poisoned by eating a misidentified fungus. Therefore, if you are not certain about the identity of a particular wild mushroom, do not consume it. Eating a poisonous mushroom can quickly lead to liver failure and death.

See also Fungicide.

Resources

books

Atlas, R.M., and R. Bartha. Microbial Ecology. Menlo Park, CA: Benjamin-Cummings Pub. Co., 1987.

Klein, R.M. The Green World. An Introduction to Plants andPeople. New York: Harper and Row, 1987.

Lincoff, G.H. The Audubon Society Field Guide to North American Mushrooms. New York: Chanticleer Press, 1981.

McKnight, K.H., and V.B. McKnight. A Field Guide to theMushrooms of North America. Boston: Houghton Mifflin Co., 1987.

Raven, Peter, R. F. Evert, and Susan Eichhorn. Biology ofPlants. 6th ed. New York: Worth Publishers Inc., 1998.

Sharma, O.P. Textbook of Fungi. New York: McGraw Hill, 1989.


Bill Freedman

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hypha (plural, hyphae)

—Cellular unit of a fungus, typically a branched and tubular filament. Many strands (hyphae) together are called mycelium.

Mutualism

—An intimate relationship between two or more organisms that is beneficial to both.

Mycelium

—This refers to thread or matlike aggregations of the fine fungal tissues known as hyphae.

Saprophyte

—This refers to an organism that derives its energy by decomposing dead organic matter. Many species of mushroom-producing fungi live off the organic debris that is present in the mineral soil and, especially, the surface litter of leaves and woody debris on the forest floor.

Mushrooms

views updated Jun 11 2018

Mushrooms

The narcotic and hallucinogenic properties of certain mushrooms have been known since ancient times. Some mushrooms were even regarded as sacred, and in some cultures their use was prohibited to ordinary people. In what is now Mexico and the southwestern United States a primary psychedelic source was peyote, a small, spineless, carrot-shaped cactus. Dried, the peyote button was consumed in various ceremonial settings. In the late nineteenth century, the use of peyote began to spread among various tribes, and early in the twentieth century strong opposition developed both among Native Americans who rejected it and whites who sought to control Native American behavior and religion.

The Native American Church was founded in 1906 at the Union Church by peyote users in Oklahoma and Nebraska. It adopted its present name in 1918 in response to a campaign by the Bureau of Indian Affairs to outlaw peyote. The fight to legalize the practices of the church has continued into the 1990s, though major rulings in the 1960s largely established the place of the church and its major sacrament.

Serious medical and scientific interest in hallucinogenic mushrooms dates from the pioneer work Phantastica: Narcotic and Stimulating Drugs by Louis Lewin (London, 1931). In this important book, Lewin discusses the use of fly agaric and identifies the peyote plant (which he named anhalonium Lewinii ) and the active substance, mescaline, obtained from it.

More than two decades later New York banker R. Gordon Wasson and his wife Valentina Wasson published their classic study Mushrooms, Russia, and History (Pantheon, 1957). This important work launched a new science of ethnomycology (i.e., the study of the role played by wild mushrooms in various human cultures throughout history). The Wassons took field trips to Mexico during 1955 to study firsthand the sacred mushroom ceremonies of the Indian people. Their record album Mushroom Ceremony of the Mazatec Indians of Mexico (Folkways Records, New York, 1957) was the first documented recording of its kind. The studies of the Wassonsalong with the popular volume by Aldous Huxley, The Doors of Perception (1954)spread interest in psychedelic drugs and their hallucinogenic properties and stand at the fountainhead of the psychedelic revolution of the 1960s.

The Wassons also gave special attention to fly agaric (A. muscaria ) in history. In his book Soma, Divine Mushroom of Immortality (1968, 1971) Wasson speculates that it was the source of the nectar named soma in the ancient Vedic literature of India. Although a few modern writers on psychedelics support the Wassons, this particular suggestion has not found support in the scholarly community.

In 1960 Timothy Leary, then an instructor at Harvard University, was introduced to the psychedelic mushroom trianactyle by a Mexican anthropologist. The experience totally disturbed his rather settled view of the universe and led directly to his launching research on psychedelic drugs at Harvard. In the process, he was introduced to LSD and very soon he left Harvard to become the advocate of a new worldview based on the mind-altering properties of hallucinogens.

Emerging as a major prophet of the mushroom was Carlos Castaneda, a South American anthropologist who seems to have worked one of the great hoaxes in history with his claims to have been taught by a mushroom-using Yaqui Indian whom he called Don Juan. His writings, using his research in the University of California library, not only influenced hundreds of thousands of readers already seeking justification for their use of psychedelics, but deceived the teachers at UCLA and many in the anthropological community who saw him as the advocate of a new methodology for the study of tribal cultures. In spite of the revelations of his deceit, Castaneda retains a loyal following.

What began as an intellectual exercise to understand tribal cultures led in the 1960s to the development of a new subculture based on the consumption of drugs, and the emergence of prophets like Richard Alpert, who found a new vision in Hinduism.

Sources:

Castaneda, Carlos. The Teachings of Don Juan. New York: Ballentine Books, 1969.

De Mille, Richard. Castaneda's Journey: The Power and the Allegory. Santa Barbara, Calif.: Capra Press, 1976.

. The Don Juan Papers. Santa Barbara, Calif.: Ross-Erikson, 1980.

La Barre, Weston. The Peyote Cult. New York: Schocken Books, 1969.

Leary, Timothy. Flashbacks. Los Angeles: Jeremy Tarcher,1983.

Masters, R. E. L., and Jean Houston. The Varieties of Psychedelic Experience. New York: Delta, 1967.

Roseman, Bernard. The Peyote Story. North Hollywood, Calif.: Wilshire Book, 1963.

mushroom

views updated May 23 2018

mush·room / ˈməshˌroōm; -ˌroŏm/ • n. a fungal growth that typically takes the form of a domed cap on a stalk, often with gills on the underside of the cap. ∎  a thing resembling a mushroom in shape: a mushroom of smoke and flames. ∎  a pale pinkish-brown color: [as adj.] a mushroom leather bag. ∎ fig. a person or thing that appears or develops suddenly or is ephemeral: he was one of those showbiz mushrooms who spring up overnight.• v. [intr.] 1. increase, spread, or develop rapidly: environmental concern mushroomed in the 1960s.2. (of the smoke, fire, or flames produced by an explosion) spread into the air in a shape resembling that of a mushroom: the grenade mushroomed into red fire as it hit the hillside. ∎  (of a bullet) expand and flatten on reaching its target.3. [usu. as n.] (mushrooming) (of a person) gather mushrooms.DERIVATIVES: mush·room·y adj.

Mushrooms

views updated May 21 2018

MUSHROOMS

MUSHROOMS , fungus. Israel is rich in various species of mushroom which grow chiefly in the winter. A large number of them are poisonous. The poisonous ones are mainly of the genus Amanita. Easily recognizable among edible mushrooms are those of the genus Boletus, called in modern Hebrew orniyyot because they grow on the roots of the pine (mod. Heb. oren), of which most of the forests planted in Israel consist. The mushroom is not mentioned in the Bible, though some exegetes (Rashi, D. Kimi) identify it with the poisonous pakku'ot of ii Kings 4:39–40. The pakku'ot, however, are the colocynth. In rabbinic literature the combination kemehim u-fitriyyot ("truffles and mushrooms") is usually found. They have in common that, although they "grow in the soil," one does not recite over them the blessing for vegetables but the blessing "by whose word everything was created." The Talmud gives as the reason that, unlike ordinary plants, "they do not draw their nourishment from the ground but from the air" (Ber. 40b). In this way they explained the fact that they possess no true roots, being fed by other plants, and absorbing moisture from the air. Mushrooms and truffles are also exempt from tithes (see: *Ma'aser), "because they do not grow by being sown, or, because the earth extrudes them" (tj, Ma'as. 1:1, 48d). The latter reason refers to their quick growth, which makes it seem as if the earth is expelling them. The extensive sprouting of mushrooms after rain is reflected in the aggadah about *Honi ha-Ma'agel who prayed for rain after drought. After rain had fallen in abundance and the heavens were free from clouds "the people went into the fields and brought home mushrooms and truffles" (Ta'an. 23a). Truffles are found chiefly in the light soils of the Judean wilderness and in the sands of the Negev. In contrast to mushrooms, they grow under the surface. In addition to kemehim, truffles are called shemarka'im (Uk. 3:2) in the Mishnah.

bibliography:

Loew, Flora, 1 (1928), 26–44.

[Jehuda Feliks]

mushrooms

views updated May 17 2018

mushrooms Various edible fungi (botanically both mushrooms and toadstools); correctly the fruiting bodies of the fungi. Altogether some 300 species are sold, fresh or dried, in markets around the world; most of these are gathered wild rather than cultivated.

The common cultivated mushroom, including flat, cup, and button mushrooms is Agaricus bisporus, as is the chestnut or Paris mushroom. Other cultivated mushrooms include: shiitake (or Black Forest mushroom); oyster mushroom; Chinese straw mushroom.

Some wild species are especially prized, including field mushroom; horse mushroom; parasol mushroom; beefsteak fungus; blewits; wood blewits; cep or boletus; chanterelle; matsutake; puffballs; morels; truffles; wood‐ears (or Chinese black fungus); yellow mushroom. Many other wild fungi are also edible, but many are poisonous.

A 50‐g portion provides 1.5 g of dietary fibre and is a rich source of copper; a source of vitamin B2, niacin, folate, and selenium; supplies 6 kcal (25 kJ).

toadstool

views updated Jun 11 2018

toad·stool / ˈtōdˌstoōl/ • n. the spore-bearing fruiting body of a fungus, typically in the form of a rounded cap on a stalk, esp. one that is believed to be inedible or poisonous. See also mushroom.

toadstool

views updated May 29 2018

toadstool A loose term for any umbrella-shaped fungal fruit body, or for any such fruit body that is inedible or poisonous. Compare MUSHROOM.

mushroom

views updated May 29 2018

mushroom Agaricus bisporus (the cultivated mushroom) or any edible fungus similar to it in appearance. Compare TOADSTOOL.

mushroom

views updated May 23 2018

mushroom Any of numerous relatively large fleshy fungi, many of which are gathered for food. A typical mushroom consists of two parts: the mycelium – an extensive, underground cobweb-like network of fine filaments (hyphae), which is the main body of the fungus – and a short-lived fruiting body (the visible mushroom).