Psilocybe samuiensis

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Psilocybe samuiensis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Hymenogastraceae
Genus: Psilocybe
P. samuiensis
Binomial name
Psilocybe samuiensis
Guzmán, Bandala & J.W.Allen (1993)
Psilocybe samuiensis
View the Mycomorphbox template that generates the following list
Gills on hymenium
Cap is conical or umbonate
Hymenium is adnate
Stipe is bare
Spore print is purple-brown
Ecology is saprotrophic
Edibility is psychoactive

Psilocybe samuiensis is a psychedelic mushroom, which has psilocybin and psilocin as main active compounds. It was placed in the section Mexicanae of genus Psilocybe by Gastón Guzmán due to its rhomboid-shaped spores. It has been found in Koh Samui, a small tropical island in Thailand, where some psychoactive species are consumed by both natives and tourists. Chao Samui rarely consume psilocybian fungi. Such local use is usually restricted to local females who do so at the request of foreigners.[1][2]


The cap is typically 7–15 mm in diameter, almost convex to conic in shape, umbonate with a small papilla. The cap is viscid and has a separable pellicle. It is a reddish-brown color when moist, but becomes lighter brown when dry. The stipe is 4.0–6.5 cm high × 1.5 cm thick, equal or slightly bulbous. The stipe is hollow, whitish in color, and covered with white fibrils. It is the same color as the cap, and stains blue when bruised. The odor and taste are slightly like grain meal (farinaceous). Spores have been recorded in the range of 10.4-12.8 by 6.4-8 μm and have a thick wall with a flattened, broad germ pore.


Psilocybe samuiensis was first picked in soil containing mixtures of sand and clay west of the village of Ban Hua Thanon, in Koh Samui. Since then it is now known to occur in Ranong Province in Thailand and also at Angkor Wat in Siem Riap, Kampuchea; and verified by Gaston Guzman. It grows scattered to gregarious in rice paddies, but never directly on manure, fruiting from early July to late August. Gastón Guzmán mistakenly noted that the species was known only by the native children who collect psychoactive fungi for sale. Only three local children observed John W. Allen harvesting fresh specimens of the species, yet days later could not remember said species.[3][2]


Analysed by HPLC and TLC, psilocybin and psilocin in the fruit bodies ranged from 0.023–0.90% (dry weight) and 0.05–0.81%, respectively. baeocystin was also detected at the concentration of 0.01–0.05%.[4]

See also[edit]


  1. ^ Allen JW, Merlin MD. (1992). "Psychoactive fungi use in Koh Samui and Koh Pha-Ngan, Thailand". Journal of Ethnopharmacology 35(3): 205–228.
  2. ^ a b Allen, John W.; Sihanonth, Prakitsin; Gartz, Jochen; Toro, Gianluca (2012). "An Ethnopharmacological and Ethnomycological Update on the Occurrence, Use, Cultivation, Chemical Analysis, and SEM Photography of Neurotropic Fungi from Thailand, Cambodia and other Regions of South and Southeast Asia, Indonesia and Bali" (PDF). Ethnomycological Journals: Sacred Mushroom Studies. 9: 1–129.
  3. ^ Guzmán, Gastón; Bandala, Victor M.; Allen, John W. (1993). "A new bluing Psilocybe from Thailand". Mycotaxon. 46: 155–160.
  4. ^ Gartz J, Allen JW, Merlin MD. (1994). "Ethnomycology, biochemistry, and cultivation of Psilocybe samuiensis Guzmán, Bandala and Allen, a new psychoactive fungus from Koh Samui, Thailand". Journal of Ethnopharmacology 43(2): 73–80.

Further reading[edit]

  • Stamets, Paul (1996). Psilocybin Mushrooms of the World. Berkeley: Ten Speed Press. ISBN 0-9610798-0-0.