Though generally considered poisonous, Amanita muscaria is otherwise famed for its hallucinogenic properties with its main psychoactive constituent being the compound muscimol. Used as an intoxicant by the Koryaks of the Kamchatka Krai of eastern Siberia, the mushroom has had a religious significance in Siberian culture and possibly also in ancient Scandinavian culture. The American banker and amateur ethnomycologist R. Gordon Wasson proposed the fly agaric was in fact the Soma talked about in the ancient Rig Veda texts of India; although this theory has been refuted by anthropologists, it gained common credence when first published in 1968.
The common name in English is thought to have been derived from its European use as an insecticide, sprinkled in milk. 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 alternative 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.
The 16th century Flemish botanist Charles de l'Écluse localised the practice to Frankfurt in Germany, while the father of taxonomy Linnaeus reported it from Småland in southern Sweden where he had lived as a child. He officially described it in Volume Two of his Species Plantarum in 1753, giving it the name Agaricus muscarius, the specific epithet deriving from Latin musca meaning "fly". It gained its current name in 1783, when placed in the genus Amanita by Jean-Baptiste Lamarck and sanctioned by Elias Magnus Fries.
The starting date had been formerly set as January 1st 1821, the date of the works of the 'father of mycology', Swedish naturalist Elias Magnus Fries, and under these conditions, the full name was Amanita muscaria (L.:Fr.) Hook.. However, a recent revision of the International Code of Botanical Nomenclature in 1987 changed the rules regarding the starting date and primary work for names of fungi, and now names can be considered valid as far back as May 1st 1753, the date of publication of Linneaus' seminal work. Hence, Linnaeus and Lamarck become the authorities and the name has become Amanita muscaria (L.) Lam.
English mycologist John Ramsbottom reported it was used for getting rid of bugs in England and Sweden, and bug agaric was an old alternate name. French mycologist Pierre Bulliard tried to replicate its fly-killing properties without success in his work Histoire des plantes vénéneuses et suspectes de la France, and proposed a new binomial name Agaricus pseudo-aurantiacus because of this.
An alternative 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. Several regional names appear to be linked with this connotation, meaning either 'mad- or 'fool's Amanita caesarea. Hence there is oriol foll 'mad oriol' in Catalan, mujolo folo from Toulouse, concourlo fouolo from the Aveyron department in Southern France, ovolo matto from the Province of Trento in Italy. A local dialect name in Fribourg in Switzerland is tsapi de diablhou 'Devil's hat'.
The word toadstool in English does not refer to any particular species, yet it has a more definite specific connotation with A. muscaria in continental Europe. Yet another name is crapaudin in many parts of France, and a Basque term from Guipúzcoa and Biscay is amoroto, all alluding to toads. Finally, a common name from China is ha-ma chün 'toad mushroom' (蛤蟆菌). Interestingly, the toad lacks the negative connotations in Chinese culture and symbolism.
Wasson proposed this was due to its being a shamanic and also taboo object and hence unable to be named specifically in ancient Celtic culture. He speculates that the power of this taboo may have perpetuated its malign reputation while other lethal fungi such as the death cap (A. phalloides) have had little cultural connotations throughout European history.
Ethnobotanist and ethnomycologist Giorgio Samorini has proposed a symbiotic relationship between toads, flies and the fly agaric. After a lick of A. muscaria, flies become inebriated and delirious prey for hungry toads that may have learned this, therefore hanging out around toadstools. This relationship within nature illuminates an etymological keystone and example of zoopharmacognosy. This would also provide further biosemiotic insight into the ancient mystery of toads, flies and mushrooms appearing together in popular mythology and fairy lore. However it is more commonly thought that toads are associated with the mushroom because they symbolise toxicity and chthonic forces in the same way that serpents do.
Amanita section Amanita consists of A. muscaria and its close relatives, including A. pantherina (the panther cap), 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 varies considerably in its morphology 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:
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.
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 in) 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 in), 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. It can be quite wide and flaccid with age. There is generally no associated smell other than a mild earthiness.
Fly 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 amarill is a common name of A. 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 native vermilion grisette (Amanita xanthocephala), which grows in association with Eucalypts. The latter species generally lacks the white warts of A. muscaria and bears no ring.
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, and may appear in fairy rings. 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).
Deaths from A. muscaria are extremely rare. A historical journal article reported two fatalities occurring in North America. With modern medical treatment the prognosis is generally good. A fatal dose has been calculated at approximately 15 fly agaric caps, although 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 acid and muscimol compared to fall fruitings. Many older books mistakenly 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 death cap (A. phalloides) or one of the several Amanita species known as destroying angel.
The active constituents of this species are water soluble, and boiling and then discarding the cooking water will at least partly detoxify A. muscaria. However, drying may increase potency as the process facilitates the conversion of ibotenic acid to the more potent muscimol. According to some sources, once detoxified, the mushroom becomes edible. In Sanada, Japan, fly agarics are detoxified by pickling them.
Ibotenic acid and muscimol are structurally related to each other and 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, while ibotenic acid is an agonist of NMDA glutamate receptors and certain metabotropic glutamate receptors) which are involved in the control of neuronal activity. It is these interactions which are thought to cause the psychoactive effects found in intoxication. Following ingestion some of the ibotenic acid is metabolised to muscimol which would appear to be the agent responsible for the majority of the psychoactivity. Indeed, ibotenic acid's strong water solubility means that it could not distribute into the brain without an active process like a transporter; this, and the lack of any reports of permanent brain damage following A. muscaria ingestion (which would be the result of ibotenic acid entering the brain due to its effect as an NMDA receptor agonist) make it unlikely that ibotenic acid enters the brain following A. muscaria ingestion. However, it is worth noting that no studies have directly investigated ibotenic acid's ability to permeate the brain.
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 erubescens or small white Clitocybe species C. dealbata and C. rivulosa, and are too insignificant to play a role in the symptoms of poisoning.
Amanita muscaria and related species are known as effective accumulators of vanadium (up to 500 mg/kg in dry weight). Vanadium is present as an organometallic compound (called amavadine) in fruit-bodies. However, the biological importance of the accumulation process is unknown.
Unlike the hallucinogenic mushrooms of the Psilocybe, Amanita muscaria has been rarely consumed recreationally. It is classified as an unscheduled drug in the United States. Any sales of A. muscaria for human ingestion are regulated by the Food and Drug Administration. Most other countries do not have laws against the use of A. muscaria, as it is currently legal and un-controlled under United Nations international law. However, following the outlawing of psilocybin-containing mushrooms in the United Kingdom, an increased quantity of Amanita mushrooms began to be sold and consumed.
In eastern Siberia, the shaman would consume the mushrooms, and others would drink his urine. This urine, still containing active hallucinogens may actually be more potent than the A. muscaria mushrooms with fewer negative effects, such as sweating and twitching, suggesting that the initial user may act as a screening filter for other components in the mushroom. Among the Koryak, one report held 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.
The Koryak of eastern Siberia have a story about the fly agaric (wapaq) which enabled Big Raven to carry a whale to its home. In the story, the deity Vahiyinin ("Existence") spat onto earth, and his spittle became the wapaq, and his saliva becomes the warts. After experiencing the power of the wapaq, Raven was so exhilarated that he told it to grow forever on earth so his children, the people, can learn from it.
Beyond Siberia, there are only isolated and unconfirmed reports of the hallucinogenic use of A. muscaria. One source mentions that it was once used among the Sami people, but no firsthand accounts of this exist. Hartmut Geerken claims to have discovered a tradition of recreational use of this mushroom among a Parachi-speaking group in Afghanistan. There are also unconfirmed reports of religious use of A. muscaria among two Subarctic Native American tribes, the Ojibway and the Dogrib. Authors of Sacred Soma Shamans Hawk and Venus have used A. muscaria as a sacrament and daily medicinal tonic since 1979.
, although a Psilocybe species has also been suggested.Fly agarics have been featured in paintings since the Renaissance
, albeit in a subtle manner. In the Victorian era they became more visible, even becoming the main topic of some fairy paintings
, usually inspired by Shakespeare's A Midsummer Night's Dream. The waning of Romanticism and the advent of World War I reduced interest in fairies along with fly agarics, reducing them to the realm of childish fantasies.
Fly agarics appear on Christmas cards and New Year cards from around the world as a symbol of good luck. They also function as Christmas tree decorations
, derived from their ectomycorrhizal relationship with coniferous trees. The ethnobotanist Jonathan Ott has suggested that the idea of Santa Claus and tradition of hanging stockings over the fireplace is based centrally upon the fly agaric mushroom itself. With its generally red and white color scheme, he argues that Santa Claus's suit is related to the mushroom. He also draws parallels with flying reindeer: reindeer had been reported to consume the mushroom and prance around in an intoxicated manner afterwards. Until the 20th century the red-and-white Santa suit familiar today was not firmly established, although Saint Nicholas, on which Santa Claus is partly based, was always depicted in red (see also: Origins of Santa Claus). One scholar researching possible links between religious myths and the red mushroom notes, "If Santa Claus had but one eye [like Odin], or if magic urine had been a part of his legend, his connection to the Amanita muscaria would be much easier to believe."
Ott also speculates about Santa's bag of toys. According to historians, ancient Siberia was one of the first civilizations to use fly agaric in practice. The Siberian hut, or yurt, is equipped with a smokehole at the top. Ott suggests that a shaman entered the yurt through the smokehole with a sack of mushrooms in his hand, to be placed in stockings over the fireplace where they could be dried for celebratory use.

