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Amanita muscaria (also known by the English-language common name fly agaric or Fly Amanita) is a psychoactive agaric species of mushroom found commonly throughout much of the world. The quintessential toadstool, it is a large imposing white-gilled, white-spotted, usually deep red mushroom, one of the most recognizable and widely encountered in popular culture. Though it is generally considered poisonous, Amanita muscaria is otherwise famed for its hallucinogenic properties with its main psychoactive constituent being the compound muscimol. The mushroom has had a religious significance in Siberian culture and possibly also in ancient Indian and Scandinavian cultures.
Native throughout the temperate and boreal regions of the Northern Hemisphere, Amanita muscaria has been unintentionally conveyed to many countries in the Southern Hemisphere, generally as a symbiont with pine plantations, and is now a true cosmopolitan species.
The common names in English, fly agaric or fly mushroom, are generally thought to derive from its European use as an insecticide, sprinkled in milk.[1] This interpretation is supported by the mushroom's names in a number of other languages (see below), e.g. French Amanite tue-mouches, i.e. "fly-killer amanita". The fly-killing agent is now known to be ibotenic acid. Another compound isolated from the fungus is 1,3-diolein which is an insect attractor. An alternate derivation proposes that the term fly- refers not to insects as such but rather the delirium resulting from consumption of the fungus. This is based on the medieval belief that flies could enter a person's head and cause mental illness.
Taxonomy and naming
Similar to its English common name, the German, Fliegenpilz, Dutch Vliegenzwam, Swedish Röd flugsvamp, Danish Rød fluesvamp, Finnish punakärpässieni, Polish muchomór, Slovak muchotrávka and French Amanite tue-mouches, are derived from this property. The various common names come from its European use as an insecticide, sprinkled in milk. Fly agaric is still used in this manner in parts of eastern Europe such as Poland and Romania. This practice was first recorded by Albertus Magnus in his work De vegetabilibus sometime before 1256, commenting:vocatur fungus muscarum, eo quod in lacte pulverizatus interficit muscas
("It is called the mushroom of flies, because crushed in milk it kills flies")
This was known to Linnaeus who gave it the name Agaricus muscarius, the specific name deriving from Latin musca meaning "fly".
In England and Sweden it was also used for getting rid of bugs, and bug agaric was an old alternate name.
Amanita muscaria is the type species of the genus Amanita. By extension, it is also the type species of Amanita subgenus Amanita, as well as section Amanita within this subgenus. Amanita subgenus Amanita includes all Amanita with inamyloid spores. Amanita section Amanita includes those species with patchy universal veil remnants, including a volva that is reduced to a series of concentric rings and the veil remnants on the pileus being a series of patches or warts. Most species in this group also have a bulbous base.
Classification
Amanita section Amanita consists of A. muscaria and its close relatives, including A. pantherina (the panther agaric), Amanita gemmata, A. farinosa, and A. xanthocephala.Modern fungal taxonomists have classified Amanita muscaria and its allies this way based on gross morphology and spore inamyloidy. Two recent molecular phylogenetic studies have confirmed this classification as natural.
Amanita muscaria var. guessowii has a yellow cap surface.
Middlesex Fells, MassachusettsAmanita muscaria has considerable morphological variation and many authorities recognize a number of subspecies or varieties within the species. In The Agaricales in Modern Taxonomy, Rolf Singer listed three subspecies, though without description: A. muscaria ssp. muscaria, A. muscaria ssp. americana, and A. muscaria ssp. flavivolvata.
Contemporary authorities recognize up to seven varieties:var. muscaria, the typical red-and-white spotted variety. Some authorities, such as Rodham Tulloss, only use this name for Eurasian and western Alaskan populations.
var. flavivolvata is red, with yellow to yellowish-white warts, and occurs in the western regions of the North American continent, from southern Alaska down through the Rocky Mountains, through Central America, to at least Andean Colombia. Rodham Tulloss uses this name to describe all "typical" A. muscaria from indigenous New World populations from Alaska southward.
var. alba, an uncommon fungus, has a white to silvery white cap with white warts but otherwise similar to the usual form.
var. formosa, has a yellow to orange-yellow cap with yellowish or tan warts and stem. Some authorities use this name for all A. muscaria fitting this description worldwide (cf, Jenkins), others (cf, Tulloss) restrict its use to Eurasian populations.
var. guessowii is yellow to orange, with center of cap more orange or reddish orange than the outer part. It is found throughout North America, but is most common in northeastern North America, from Newfoundland and Quebec down to Tennessee. Some authorities (cf, Jenkins) treat these populations as part of A. muscaria var. formosa, while others (cf, Tulloss) recognize it as a distinct variety.
var. persicina is pinkish to orangish "melon" colored with poorly formed or absent remnants of universal veil on the stem and vasal bulb, known from the Southeastern Coastal areas of the U.S.A, described in 1977.
var. regalis (= Amanita regalis (Fr.) Michael), from Scandinavia and Alaska, is liver-brown and has yellow warts. It appears to be uniformly distinctive and some authorities (cf, Tulloss) treat it as a separate species, while others (cf, Jenkins) treat it as a variety of A. muscaria.
A 2006 molecular phylogenetic study of different regional populations of A. muscaria by Geml, et al. found three distinct clades within this species representing, roughly, Eurasian, Eurasian "subalpine", and North American populations. (Alaska contains examples of all three clades, leading to the hypothesis that this was the center of diversification of this species.) The study also looked at four named varieties of this species; var. alba, var. flavivolvata, var. formosa (including var. guessowii), and var. regalis from both areas. All four varieties were found within both the Eurasian and North American clades, evidence that these morphological forms are simply polymorphisms found throughout the species rather than distinct subspecies or varieties.
Description
A large conspicuous mushroom, Amanita muscaria is generally common and numerous where it grows, often being found in groups with basidiocarps in all stages of development. Fully grown, the bright red cap is usually around 8-20 cm (3-8 inches) in diameter, though larger specimens have been found. The red colour may fade after rain and in older mushrooms. After emerging from the ground, the cap is covered with numerous small white to yellow flecks (warts) which are remnants of the universal veil, a membrane that encloses the entire mushroom when it is still very young. The gills are white, as is the spore print. The stem is white, 5-20 cm high (approximately 2-8 inches), with a basal bulb that bears universal veil remnants (more or less distinct rings or ruffs), and has the slightly brittle, fibrous texture typical of many large mushrooms. Between the basal universal veil remnants and gills are remnants of the partial veil (which covers the gills during development) in the form of a white ring (annulus). It can be quite wide and flaccid in age. There is generally no associated smell other than a mild earthiness.
A mature Amanita muscaria, showing a flat pileus
near Tyndrum, ScotlandFly agaric fruiting bodies emerge from the soil looking like a white egg, covered in the white warty material of the universal veil. As the fungus grows, the red colour appears through the broken veil, and the cap changes from hemispherical to plate-like and flat in mature specimens.
Though very distinctive, the fly agaric has been mistaken for other yellow to red species in the Americas such as Armillaria cf. mellea and the edible Amanita basii, a Mexican species similar to A. caesarea of Europe. Poison control centers in the U.S. and Canada are aware that "amarillo" is a common name of caesarea-like species in Mexico, not just the Spanish for 'yellow'.
Amanita caesarea can be distinguished as it has an entire orange red cap, lacking the numerous white warty spots of the fly agaric. Furthermore the stem, gills and ring are bright yellow, not white.
Finally the volva is a distinct white bag, not broken into scales.
In Australia, the introduced fly agaric may be confused with the local Amanita xanthocephala, which grows in association with Eucalypts. This species also generally lacks the white warts of A. muscaria and bears no ring.
Distribution and habitat
A. muscaria is a cosmopolitan mushroom, native to birch, pine, spruce, fir and cedar woodlands throughout the temperate and boreal regions of the Northern Hemisphere, including high elevations of warmer latitudes in regions like the Hindu Kush, the Mediterranean and Central America. Interestingly, a recent molecular study proposes an ancestral origin in the Siberian–Beringian region in the Tertiary period before radiating outwards across Asia, Europe and North America. Though generally encountered in autumn, the season can vary in different climates: fruiting occurs in summer and autumn across most of North America, but later in autumn and early winter on the Pacific coast. It is often found in similar locations to Boletus edulis. It has been widely transported into the southern hemisphere, including Australia, New Zealand, South Africa and South America, where it usually occurs under introduced pine trees.
The fungal equivalent of a weed in southeastern Australia, it appears to have formed new associations with southern beech (Nothofagus) in Tasmania and Victoria and invading native rain forest, where there are concerns it may be displacing native species. Furthermore it appears to be spreading northwards with recent reports near Port Macquarie on the New South Wales north coast.
When imported to a new country, A. muscaria can jump to native species (for example, Eucalyptus in Australia). It can then be exported with its new symbiont (for example, from Australia to Argentina).
Biochemistry
Amanita muscaria contains a number of biologically active agents, at least two of which are known to be psychoactive. Muscimol (3hydroxy-5-aminomethy-1 isoxazole, an unsaturated cyclic hydroxamic acid) is the most significant. It is the product of the decarboxylation or drying of ibotenic acid, another important compound in the biochemistry of the fly agaric. Muscarine, discovered in 1869, was long thought to be the active hallucinogenic agent in A. muscaria until the mid 20th century,when researchers in England, Japan, and Switzerland recognized that these effects were due mainly to ibotenic acid and muscimol.
Ibotenic acid and muscimol are structurally related to two major neurotransmitters of the central nervous system: glutamic acid and GABA respectively. Ibotenic acid and muscimol act like these neurotransmitters (muscimol is a potent GABAA agonist) which are involved in the control of neuronal activity. It is these interactions which are thought to cause the brain dysfunction found in intoxication. Following ingestion some of the ibotenic acid is decarboxylated to muscimol which would appear to be the agent responsible for the majority of the psychoactivity. When muscimol is administered, it has been shown active in the cerebral cortex, hippocampus, and cerebellum.
Muscazone is another compound more recently isolated from European specimens of the fly agaric. It is a product of the breakdown of ibotenic acid by ultra-violet radiation. It is of minor pharmacological activity compared with the other agents.
Muscarine binds with Muscarinic acetylcholine receptor and lead to the excitation of the neurons bearing these receptors. The levels in Amanita muscaria are minute when compared with other poisonous fungi, such as the deadly Inocybe patouillardii or small white Clitocybe species C. dealbata and C. rivulosa.
Toxicity
Victims of Amanita muscaria poisoning are generally either young children or people ingesting it for a hallucinogenic experience.About one gram of A. muscaria or 50-100 mg ibotenic acid is considered a toxic dose. Ibotenic acid, a compound present in A. muscaria, is a powerful neurotoxin that is used as a "brain-lesioning agent" and has shown to be highly neurotoxic when "injected directly into the brains of mice and rats."
Fly agarics are known for the unpredictability of their effects. Depending on habitat and the amount ingested per body weight, effects can range from nausea and twitching to drowsiness, cholinergic effects (low blood pressure, sweating and salivation), auditory and visual distortions, mood changes, euphoria, relaxation, and loss of equilibrium. Retrograde amnesia frequently results following recovery.
In cases of serious poisoning it causes a delirium, characterized by bouts of marked agitation with confusion, hallucinations, and irritability followed by periods of central nervous system depression. Seizures and coma may also occur in severe poisonings.Effects typically appear after around 30 to 90 minutes and peak within three hours, but certain effects can last for a number of days.
In the majority of cases recovery is complete within 12 hours. The effect is highly variable and individuals can react quite differently to the similar doses.
Deaths from A. muscaria are extremely rare. A historical journal article reported 2 fatalities occurring in North America. With modern medical treatment the prognosis is generally good.
The amount and ratio of chemical compounds per mushroom varies widely from region to region, season to season, further confusing the issue. It has been reported that spring and summer mushrooms may contain up to 10 times as much ibotenic/muscimol as compared to fall fruitings. Many older books list it as deadly, giving the impression that it is far more toxic than it really is. The vast majority of mushroom poisoning fatalities (90% or more) are from having eaten either the greenish to yellowish to brownish mottled death cap (A. phalloides) or one of the destroying angels (Amanita virosa).
The toxic substances of A. muscaria are water soluble and susceptible to heat. The mushroom can be at least partly detoxified by thoroughly parboiling or leaching it in boiling water because it is said that the ibotenic acid turns into muscimol under this heat. This supposedly removes several unpleasant side effects due to the conversion of the much more toxic ibotenic acid into muscimol. According to some sources, once detoxified, the mushroom becomes edible.
In Sanada, Japan fly agarics are detoxified by pickling them.
Psychoactive properties
A basket of A. muscaria.In contrast to hallucinogenic mushrooms of the Psilocybe, Amanita muscaria is rarely consumed recreationally. It is unscheduled in the United States. Any sales of A. muscaria for human ingestion are regulated by the FDA. Most other countries do not have laws against the use of A. muscaria, as it is currently legal and un-controlled under UN international law. However, following the outlawing of psilocybin containing mushrooms in the UK, an increased quantity of Amanita mushrooms began to be sold and consumed.
The active ingredient is excreted in the urine of those consuming the mushrooms, and it has sometimes been the practice for a shaman to consume the mushrooms, and the rest of the tribe to drink his urine: the shaman, in effect, partially detoxifying the drug (the sweat- and twitch-causing muscarine is absent in the urine). This was also not an uncommon practice in Siberia, where the poor would consume the urine of the wealthy, who could afford to buy the mushrooms. If a fly agaric is eaten, it is usually not fresh, but in its dried or cooked form, where ibotenic acid is converted to the more stable and far less poisonous muscimol.
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Very Nice picture, wonderful color.