| Psilocybe | |
|---|---|
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| Psilocybe semilanceata | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Agaricales |
| Family: | Hymenogastraceae |
| Genus: | Psilocybe (Fr.)P.Kumm. (1871) |
| Type species | |
| Psilocybe semilanceata | |
| Species | |
| Synonyms[1] | |
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Psilocybe (/ˌsaɪloʊˈsaɪbi/SY-loh-SY-bee)[2] is agenus of gilledmushrooms, growing worldwide, in the familyHymenogastraceae. Many species contain thepsychedelic compoundspsilocybin andpsilocin.
A 2002 study of themolecular phylogeny of the agarics[3] indicated the genusPsilocybe as then defined waspolyphyletic, falling into two distinctclades that are not directly related to each other. The blue-staininghallucinogenic species constituted one clade and the non-bluing species the other. The previoustype species of the genus,Psilocybe montana (nowDeconica montana), was in the non-bluing clade, but in 2010, the type species was changed toP. semilanceata, a member of the bluing clade. A 2006 molecular phylogenetic study of theAgaricales by Matheny and colleagues, further demonstrated the separation of the bluing and non-bluing clades ofPsilocybe in a larger, strongly supported phylogenetic tree of the Agaricales.[4]
Psilocybe had been placedtaxonomically in the agaric familyStrophariaceae based upon itsspore andpileipellis morphology. The phylogenetic study by Mathenyet al., placed the non-bluingPsilocybe and its close relatives in abasal position within the Strophariaceae, asister taxon to a clade containing the other genera within that family. The bluingPsilocybe, however, form a clade that is sister toGalerina in the newly revised family,Hymenogastraceae which used to be restricted to secotioid, false-truffles.[4] The phylogenetic study by Moncalvo,et al. confirmed that the agaric genusMelanotus is simply a subgroup of the non-bluingPsilocybe, all of which are placed inDeconica, and also pointed to a close relationship between the latter genus and the generaKuehneromyces andPhaeogalera.[3]
In 2007, a paper by Redheadet al. proposedconserving the genusPsilocybe withPsilocybe semilanceata as its type species.[5] The suggestion was accepted by unanimous vote of theNomenclature Committee for Fungi of the International Botanical Congress in 2010, meaning thatP. semilanceata (a member of the bluing clade) now serves as the type species of the genus.[6] SinceP. semilanceata is now the type species of the genus, the bluing hallucinogenic clade remained in the genusPsilocybe (Hymenogastraceae) while the non-bluing clade were transferred to the genusDeconica (Strophariaceae).[7] However, it has been demonstrated thatP. fuscofulva, a species which used to be known asP. atrobrunnea, belongs to the genusPsilocybe s.s., but does not contain psychotropic compounds.[8] Negative results have also been published forP. fimetaria.[9]
The genus namePsilocybe is a compound of theGreek elements ψιλός (psilós) "bare" / "naked" and κύβη (kúbe) "head" / "swelling",[10] giving the meaning "bare-headed" (i.e.bald) referring to the mushroom's detachable pellicle (loose skin over the cap), which can resemble a bald pate.
Psilocybefruit bodies are generally small, undistinguished mushrooms with a typical "little brown mushroom"morphology. Macroscopically, they are characterized by their small to occasionally medium size, brown to yellow-brown coloration, with ahygrophanouscap, and aspore print-color that ranges from lilac-brown to dark purple-brown (though rusty-brown colored varieties are known in at least one species).[11] Hallucinogenic species typically have a blue-staining reaction when the fruit body is bruised. Microscopically, they are characterized bypileipellis with hyphae that run parallel to the pileus surface, forming acutis, by their lack ofchrysocystidia, and byspores which are smooth, ellipsoid to rhomboid to subhexagonal in shape, with a distinct apicalgerm pore. Ecologically, all species ofPsilocybe aresaprotrophs, growing on various kinds of decaying organic matter.[12][13]
Geographically, species in this genus are found throughout the world in mostbiomes.[15] The greatest species diversity seems to be in theneotropics, fromMesoamerica throughBrazil andChile.[14]Psilocybe are found in a variety ofhabitats andsubstrates. Many of the species found intemperate regions, such asPsilocybe cyanescens, seem to have an affinity forlandscaped areasmulched withwoodchips and are actually rather rare in natural settings removed from human habitation.[16] Contrary to popular belief, only a minority ofPsilocybe species, such asP. cubensis andP. subcubensis, grow directly onfeces.[17] Many other species are found in habitats such asmossy,grassy, orforesthumussoils.Psilocybe arose about 65 million years ago.[18] In 2024, two newPsilocybe species (Hymenogastraceae),P. ingeli andP. maluti, were described from southern Africa.[19]
Thepsilocybin molecule is indirectly responsible for the hallucinogenic properties of thePsilocybe. This compound, as well as all otherindole alkaloids, are derived from the amino acidtryptophan, being the only amino acid with the indole-amine ring. Tryptophan is converted totryptamine bydecarboxylation.[20] Two methylation steps occur producingDMT, another psychedelic compound.[20] Hydroxylation of this compound produces the more potent hallucinogenpsilocin, followed by phosphorylation yieldingpsilocybin.[20] After ingestion of the psilocybin compoundalkaline phosphatases present in the body's digestive system, kidneys, and possibly in the blood readily cleave the phosphoryl ester bond from psilocybin, yielding the hydroxyl compound, psilocin.[21] Psilocin is the chemical primarily responsible for the hallucinogenic effects of thePsilocybe.[21] The blue-staining species ofPsilocybe are characterized by the presence of psilocin and psilocybin. This blue-staining reaction occurs after the fruit body has been injured, particularly near the base of the stalk.[22] This reaction is thought to be due to theoxidation of psilocybin after the outer surface of the fruit body has been breached.[23] The degree of bluing in aPsilocybe fruit body roughly correlates with the concentration of psilocin in the mushroom.[24] Psilocybin is chemically far more stable than psilocin, the latter compound being largely lost when the mushroom is heated or dried.[25]
The chemical structure ofserotonin, aneurotransmitter, is similar to that of psilocin. The latter differs mainly by the location of one of the hydroxyls, and the addition of two methyl groups that make the moleculelipophilic (fat soluble), ergo capable of crossing thelipid membrane sheaths of thecentral nervous system.[26] After psilocybin has been ingested and dephosphorylated, to psilocin, the mechanism it uses in the brain has a directagonist effect on the 5-HTserotonin receptors.[21] To explain this effect, the psilocin molecule essentially mimics the serotonin molecule, binding to the 5-HT receptors and initiating the same response as the serotonin. This effect explains the euphoria experienced by ingestion of this "agonist." Initially, hallucinogens were thought to blockade these serotonin neurotransmitters, but persistent research led to this agonist effect conclusion.[21]
Woolley and Campbell conducted research to determine whether the depletion of the hormone serotonin had a direct effect on mental disorders and that hallucinations might be due to an excess of serotonin.[27] Their results led them to study chemicals analogous to serotonin. They found that the psychoactive chemicals psilocybin and psilocin exhibited serotonin-like effects, however as dosage increased, these compounds acted as serotonin antagonists, psilocybin being comparable to the most potent antagonist yet discovered.[27] This is a plausible basis for the psychological effects of these hallucinogenic compounds.
Even though these chemicals are psychoactive and therefore thebasidiomycete deemed toxic, there have been no reports of fatalities or induced internal organ damage directly associated with ingestion of these chemicals.[28] Misidentification of the fruit body could lead to ingestion of a lethal fungus.
Some psychoactive species containbaeocystin,norbaeocystin andβ‐carboline monoamine oxidase inhibitors in addition to psilocin and psilocybin.[29]
The medicinal uses of thePsilocybe was recorded by Native Americans of Central America. Shamans, orcuranderas would avidly ingest the "sacred mushrooms" for the extrasensory perceptual effects it gave them in order to better assess problems faced in their society.[30] The observed effects of the alkaloids found in these mushrooms has given rise to research into their possible uses for psychiatric medicine.[30]For details on contemporary research, see:Psilocybin: Medical research.
Hallucinogenic species ofPsilocybe have a long history of use among the native peoples of Mesoamerica for religious communion, divination, and healing, frompre-Columbian times up to the present day. HallucinogenicPsilocybe were known to the aboriginalMexicans asteonanácatl (literally "divine mushroom")[31] and were reportedly served at the coronation ofMoctezuma II in 1502. After theSpanish conquest of the Americas, the use of hallucinogenic plants and mushrooms, like other pre-Christian traditions, was forcibly suppressed and driven underground.[32]
By the 20th century, hallucinogenic mushroom use was thought by non-Native Americans to have disappeared entirely. However, in 1955,Valentina Wasson andR. Gordon Wasson became the firstWesterners to actively participate in an indigenous mushroom ceremony. The Wassons did much to publicize their discovery, even publishing an article on their experiences inLife in 1957.[33] In 1956,Roger Heim identified the hallucinogenic mushroom that the Wassons had brought back from Mexico asPsilocybe and in 1958,Albert Hofmann first reported psilocin and psilocybin as the active compound in these mushrooms.[34] There is some skepticism as to whether or not these "sacred mushrooms" were actually in the genusPsilocybe. However, according to Heim's research in Mexico, he identified three species ofPsilocybe that he believed were used in these native ceremonies. The species identified by Heim were;P. mexicana, P. caerulescens, andP. zapotecorum.[35][36][37] are a variety ofPsilocybe mushrooms that make up theteonanácatl group of hallucinogenic mushrooms, includingP. cubensis.[38] Isauro Nava Garcia, a Mazatec man, provided guidance to Heim while Heim conducted his field and culture work.[39] Garcia was an avid observer of the fungi in his environment while identifying specific characteristics about the fruit body of thePsilocybe his ancestors utilized, as well as knowing where they could be found.[39]
At present, hallucinogenic mushroom use has been reported among a number of groups spanning from central Mexico to Oaxaca, including groups ofNahua,Mixtecs,Mixe,Mazatecs,Zapotecs, and others.[40]
The popularization ofentheogens by Wasson,Timothy Leary, and others has led to an explosion in the use of hallucinogenicPsilocybe throughout the world. By the early 1970s, a number of psychoactivePsilocybe species were described from temperate North America, Europe, and Asia and were widely collected. Books describing methods of cultivatingP. cubensis in large quantities were also published. The relatively easy availability of hallucinogenicPsilocybe from wild and cultivated sources has made it among the most widely used of thehallucinogenic drugs.
The purified chemicals psilocybin and psilocin are listed as Schedule II drugs under the United Nations 1971Convention on Psychotropic Substances.[41] However, the UN drug treaties do not apply to cultivation, preparation, or international transport of psilocybin mushrooms.
Internationally, the two chemicals are generally considered controlled substances. However, there is much ambiguity about what is considered a "container" of these compounds. In several countries (e.g. Brazil), the chemicals themselves are listed as controlled substances, but the mushrooms that contain the chemicals are not, therefore deemed legal.[42]In the United States, possession ofPsilocybe mushroom fruiting bodies is illegal in every state except for Florida. This is because the Supreme Court of Florida does not believe that these mushrooms could "reasonably be found to be containers of the schedule I substance, psilocybin".[43]
In the United States, there is no federal law mentioning the possession ofPsilocybe spores. This is because only the psilocybin and psilocin compounds are considered Schedule I drugs and there is no presence of these compounds in the spores themselves, only in the fruiting body of the cultivated spores. However, there are several US states that have actually prohibited possession of these spores because they can be cultivated to produce these hallucinogenic, Schedule I drugs. These states includes California, Georgia,[44] and Idaho.[42][45]
However, possession of the spores by a qualified mycologist in California is legal if being put to use for research purposes, which must be approved by Research Advisory Panel.[46] If not authorized by law, possession of spores or cultivation of fruiting bodies of thePsilocybe is punishable to no more than one year in county jail or state prison.[46]
Psilocybin mushrooms, as well as other "soft drugs" which are stronger than cannabis but not synthetic, are legally available throughsmart shops in the Netherlands. Only thetruffle form of magic mushrooms (such asP. tampanensis) are currently legal, but these still contain the active ingredients and produce similar effect as the caps and stalks.[47]
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