Revised January 9, 2005; October 16, 2007; and April 10, 2013.
Copyright 1998-2013 by John W. Allen.

Psilocybe samuiensis Guzmán, Bandala and Allen


Psilocybe samuiensis Guzmán, Bandala and Allen


Cap: 7 to 1.5 cm. Convex to conic-convex to campanulate, often umbonate with a small papilla. Translucent when moist, striate margin in young, and with a separate pellicle. Hygrophanous and fading to straw-yellow in drying.

Gills: Adnate and clay colored, than violaceous brown to chocolate-violet with whitish margins.

Stem: 40 to 60 mm. long by 1-2 mm thick. Whitish to yellowish and covered with fibrils. Enlarged at base. Partial veil cortinate leaving a superior fibrillous annular zone that soon disappears.

Spores: 9.3-13 x 5-7µ. Basidia 4-spored. Pleurocystidia scattered and ventricose towards the base.

Sporeprint: Chocolate to Purple-brown.

Habitat: Grows in well manured clay-like soils in rice paddies and open grassy areas.

Distribution: Koh Samui Island in the Gulf of Thailand and surrounding areas. Ranong Province, Thailand and at Angkor Wat, Cambodia.

Season: Late may through September and possibly into October.

Dosage: 15-1=20 fresh mushrooms.

Comments: So far this mushroom has only been found four times, fruiting in rice paddies from two locations on Koh Samui Island in the Gulf of Thailand. First in 1991 by John W. Allen in rice paddie fields near the Muslim village of Ban Hua Thanon, Koh Samui. Ten years later, a 2nd collection was gathered with Chief Ill Eagle, Travis Canaday, Nataya and Mike Acevedo, about 100 meters past where the first collection was found ten years earlier.
In 2003, JWA found 8 specimens in a second location a few miles down the road in the rice paddie fields of Na Muang, Koh Samui. And again in 2004, numerous collections were gathered from that same field during two separate fruitings in June and July of 2004. Its fruiting run is from 5 to 7 days and then they are gone from the fields.
Most likely it is probable that this species also fruits in other locations in southern Thailand and possibly Malaysia. It is not, as reported by found in Eastern Oregon. This species is closely related to Psilocybe mexicana Heim and is macroscopically similar to Psilocybe semilanceata and is the first species found outside of Mexico directly related to Psilocybe mexicana Heim. That latter species is ceremoniously used by native Americans in Mesoamerica.

Psilocybe samuiensis Guzmán, Bandala and Allen. First found in 1991 in the rice paddies of Ban Hua Thanon on Koh Samui Island in Thailand. 2nd larger discovery in Ban Hua Thanon in 2001 by Chief Ill Eagle and other participants on one of my fall expeditions in collecting Thai mushrooms for herbarium deposit at Chulalongkorn University in Bangkok. By mid-summer of 2003 and 2005, collections were made in Surat Thani Province along the Eastern Coastal region of the Gulf of Thailand and then small collections and cultivations were reported by Scott Leibler, an orchid expert in Thailand who found small fruitings of P. samuiensis in the Ranong Province close to the Andaman Sea facing India and Sri Lanka. In 2005, both Psilocybe samuiensis and Psiliocybe cubensis were observed in a new location near Na Muang, Koh Samui and then in the summer-early fall of 2005, Psilocybe samuiensis was collected and reported from Angkor Wat, Kampuchea and identified as such by Guzmán (Pers. Comm. 2005).

For the taxonomical particulars of this species see:
A New Bluing Psilocybe from Thailand

For a recent article on a new compound found in Psilocybe samueinsis see:
Psilosamuinsin A

Psilocybe samuiensis Photo Gallery

Field Collections for 1991
Field Collections for 2001
Field Collections for 2003
Field Collections for 2004-Page 1
Field Collections for 2004-Page 2
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