Psilocybe

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Psilocybe
Image:Psilocybe cyanescens.jpg
Wavy cap, Psilocybe cyanescens
Scientific classification
Kingdom:Fungi
Division:Basidiomycota
Class:Homobasidiomycetes
Order:Agaricales
Family:Strophariaceae
Genus:Psilocybe
Species

See text.

Psilocybe is a genus of fungi that is best known for its hallucinogenic species, the so-called "magic mushrooms" or teonanacatl.


Contents

Biological Aspects

Psilocybe fruiting bodies are typically small, undistinguished mushrooms with a typical "little brown mushroom" morphology. Macroscopically, they are characterized by their small to occasionally medium size, brown to orange-white coloration, hygrophanous pileus, and a spore print-color that ranges from medium gray-brown to dark purple-brown (though rusty-brown colored varieties are known in at least one species). Hallucinogenic species typically have a blue-staining reaction when the fruiting body is bruised. Microscopically, they are characterized by cutis-type pileipellis, lack of chrysocystidia, and spores that are smooth, ellipsoid to rhomboid to subhexagonal in shape, with a distinct apical germ pore. Ecologically, all species of Psilocybe are saprotrophs, growing on various kinds of decaying organic matter.

A recent study of the molecular phylogeny of the agarics by Moncalvo, et al. (2002)[1] indicates that the genus Psilocybe as presently defined is polyphyletic, falling into two distinct clades that are not directly related to each other. The blue-staining hallucinogenic species constitute one clade and the non-bluing species constitute the other. If this finding is supported by other studies, it will result in a new genus being split off from Psilocybe. Since the type species (Psilocybe montana) is a non-bluing species, the non-bluing clade will retain the name Psilocybe, while the bluing clade will be renamed as a separate genus.

Psilocybe is placed taxonomically in the agaric family Strophariaceae based upon its spore and pileipellis morphology. However, molecular studies indicate that the Strophariaceae may be a polyphyletic grouping of several clades that are fairly close to each other, but not necessarily sister taxa, hence, the precise relationship of Psilocybe to other agaric genera awaits further study. The phylogenetic study by Moncalvo, et al. (2002)[2] has confirmed that the agaric genus Melanotus is simply a subgroup of the non-bluing Psilocybe, and also points to a close relationship between the latter group and the genera Kuehneromyces and Phaeogalera.

Geographically, species in this genus are found throughout the world in most biomes, with the exception of high deserts. For the bluing Psilocybe, the greatest species diversity seems to be in the neotropics, from Mesoamerica through Brazil and Chile (Guzman 1983). Psilocybe are found in a variety of habitats and substrates. Many of the bluing species found in temperate regions, such as P. cyanescens, seem to have an affinity for landscaped areas mulched with woodchips and are actually rather rare in natural settings removed from human habitation. Contrary to popular belief, only a minority of Psilocybe species, such as P. coprophila and P. cubensis, grow directly on dung. Many other species are found in habitats such as mossy, grassy, or forest humus soils.

Chemistry and Pharmacology

The blue-staining species of Psilocybe are characterized by the presence of psilocin and psilocybin. The blue-staining reaction, while not completely understood, is thought to be a caused by a degradation reaction of psilocin, hence the degree of bluing in a Psilocybe fruiting body correlates directly with the concentration of psilocin in the mushroom. Psilocybin is chemically far more stable than psilocin, the latter compound being largely lost when the mushroom is heated or dried.

Psilocin and psilocybin are hallucinogenic compounds and are responsible for the psychoactive effects of these mushrooms. (See Psilocybin for a more in-depth discussion of the pharmacology of psilocybin and psilocin.)

Some psychoactive species contain baeocystin and norbaeocystin in addition to psilocin and psilocybin.

History and Ethnography

Hallucinogenic species of Psilocybe have a long history of use among the native peoples of Mesoamerica for religious communion, divination, and healing, from pre-Columbian times up to the present day. Mushroom-shaped statuettes found at archaeological sites seem to indicate that ritual use of hallucinogenic mushrooms is quite ancient. Mushroom stones have been found in pre-Classic sites from Guatemala to El Salvador, though there is considerable controversy whether these objects are associated with the use of hallucinogenic mushrooms or whether the objects had some other significance and the mushroom shape is simply coincidence. More concretely, a statuette dating from ca. 200 CE and depicting a mushroom strongly resembling Psilocybe mexicana was found in a west Mexican shaft and chamber tomb in Colima state.

Hallucinogenic Psilocybe were known to the Aztecs as teonanacatl and were reportedly served at the coronation of Moctezuma II in 1502. After the Spanish conquest, the use of hallucinogenic plants and mushrooms, like other pre-Christian traditions, was forcibly suppressed and driven underground.

By the 20th century, hallucinogenic mushroom use was thought by non-Indians to have disappeared entirely. Some authors even held that Mesoamerican cultures did not use mushrooms as hallucinogens at all and that the Spanish had simply mistaken peyote for a mushroom. Later investigations by Blas Reko, Richard Evans Schultes, and R. Gordon Wasson demonstrated that hallucinogenic mushrooms were still widely used by several indigenous Mesoamerican peoples, particularly the Mazatecs of Oaxaca.

At present, hallucinogenic mushroom use has been reported among a number of groups spanning from central Mexico to Oaxaca, including groups of Nahua, Mixtecs, Mixe, Mazatecs, Zapotecs, and others. There has not, however, been any confirmed observations of hallucinogenic mushroom use among the Maya peoples, either in the pre-Columbian or post-Contact eras.

Medical and Psychiatric Aspects

Social and Legal Aspects

Notable Species

  • Psilocybe cubensis, (= Stropharia cubensis); the most commonly grown and consumed Psilocybe, due to ease of cultivation and large size of carpophores; nicknamed the commercial Psilocybe.
  • Psilocybe semilanceata, found in northern temperate climates; nicknamed the Liberty Cap.
  • Psilocybe cyanescens, native to northwestern North America; nicknamed wavy-capped Psilocybe.

See "List of Psilocybe species" for a more complete list of psychoactive species.

References and Further Reading

  • Guzman, Gaston. 1983. The Genus Psilocybe: A Systematic Revision of the Known Species Including the History, Distribution and Chemistry of the Hallucinogenic Species. (Beihefte zur Nova Hedwigia 74.) Vaduz, LI: J. Cramer. [out of print]
  • Metzner, Ralph (ed). 2005. Sacred Mushroom of Visions: Teonanácatl [2nd ed]. Rochester, VT: Park Street Press. 304 pp. [3]
  • Stamets, Paul. 1996. Psilocybin Mushrooms of the World. Berkeley: Ten Speed Press. 245 pp. [4]

External links

See also: Psychedelic mushrooms

Retrieved from "http://en.freepedia.org/Psilocybe.html"


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