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.[1]


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).


Psilocybe samuiensis was first picked in soil containing mixtures of sand and clay west of the village of Ban Hua Thanon, in Koh Samui. It grows scattered to gregarious in rice paddies, fruiting from early July to late August.[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%.[3]


  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. Guzmán G, Bandala VM, Allen JW. (1993). "A new bluing Psilocybe from Thailand". Mycotaxon46: 155–160.
  3. 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

  • Stamets, Paul (1996). Psilocybin Mushrooms of the World. Berkeley: Ten Speed Press. ISBN 0-9610798-0-0. 
This page uses content from the English Wikipedia. The original article was at Psilocybe samuiensis. The list of authors can be seen in the page history.

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