Psilocybe baeocystis
Psilocybe baeocystis Singer & A.H. Sm 373850.jpg
Scientific classification edit
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Hymenogastraceae
Genus: Psilocybe
P. baeocystis
Binomial name
Psilocybe baeocystis
Singer & A.H.Smith (1958)
Psilocybe baeocystis
View the Mycomorphbox template that generates the following list
gills on hymenium
cap is convex or conical
hymenium is adnate or sinuate
stipe is bare
spore print is purple-brown
ecology is saprotrophic
edibility: psychoactive

Psilocybe baeocystis is a psilocybin mushroom of the family Hymenogastraceae. It contains the hallucinogenic compounds psilocybin, psilocin and baeocystin. The species is commonly known by various names such as bottle caps, knobby tops, blue bells, olive caps.

Etymology and history


Microscopic features

Psilocybe baeocystis spores are dark purplish brown in deposit, oblong in face view or asymmetric ellipsoid (mango form) in side view, and are (8.5) 9.5–13.7(17) x (5) 5.5–6.6(7.1) μm.[6] The basidia are 4-spored, and pleurocystidia are absent. The cheilocystidia are 20–30(40) x 4.5–6(9) μm and fusiod with a narrow neck.[7]

This species closely resembles subtropical Psilocybe aztecorum and Psilocybe quebecensis, which also have caps that bleach in color to white when dry.[6]

Psilocybe baeocystis spores 1000x
Psilocybe baeocystis spores 1000x

Habitat and distribution

Psilocybe baeocystis is solitary to cespitose, and scattered to numerous on ground bark, wood chips, peat moss, decaying conifer mulch, occasionally on lawns, pastures, and rarely in coniferous forests. Often found growing under plants like rhododendrons and rose bushes in mulched garden beds, sometimes growing amongst other Psilocybe species such as Psilocybe stuntzii and Psilocybe cyanescens. Psilocybe baeocystis grows from August through December, and rarely as early as the end of June. Psilocybe baeocystis is a hemiboreal mushroom, common throughout the Pacific Northwest.


Psilocin was first reported in this species in Benedict et al., 1962,[2] and a few years later, Leung and Paul would report the related compound baeocystin, isolated from saprophytic culture,[3] as well as the desmethyl metabolite norbaeocystin.[4] Beug and Bigwood (1981) also reported on the concentrations of these compounds in Psilocybe baeocystis using reverse-phase HPLC and thin-layer chromatography.[5] Concentration ranges for psychoactive compounds from these studies were reported to be 0.15–0.85% psilocybin, up to 0.59% psilocin, and up to 0.10% baeocystin.


This mushroom has been placed in the section Aztecorum by Gaston Guzman; other members of the section include Psilocybe aztecorum var. aztecorum, Psilocybe aztecorum var. bonetii, Psilocybe pseudoaztecorum, and Psilocybe quebecensis.


  1. ^ a b Singer, R.; Smith, A.H. (1958). "New species of Psilocybe". Mycologia. 50 (1): 141–142. doi:10.2307/3756045. JSTOR 3756045.
  2. ^ a b Benedict RG, Brady LR, Tyler VE (April 1962). "Occurrence of psilocin inPsilocybe baeocystis". J Pharm Sci. 51 (4): 393–4. doi:10.1002/jps.2600510428. PMID 13867140.
  3. ^ a b Leung AY, Paul AG (January 1967). "Baeocystin, a mono-methyl analog of psilocybin from Psilocybe baeocystis saprophytic culture". J Pharm Sci. 56 (1): 146. doi:10.1002/jps.2600560132. PMID 6067681.
  4. ^ a b Leung AY, Paul AG (October 1968). "Baeocystin and norbaeocystin: new analogs of psilocybin from Psilocybe baeocystis". J Pharm Sci. 57 (10): 1667–71. doi:10.1002/jps.2600571007. PMID 5684732.
  5. ^ a b Beug MW, Bigwood J (March 1981). "Quantitative analysis of psilocybin and psilocin in Psilocybe baeocystis (Singer and Smith) by high-performance liquid chromatography and by thin-layer chromatography". J. Chromatogr. 207 (3): 379–85. doi:10.1016/S0021-9673(00)88741-5. PMID 7194879.
  6. ^ a b Guzmán, Gastón (Mar–Apr 1978). "Variation, distribution, ethnomycological data and relationships of Psilocybe aztecorum, a Mexican hallucinogenic mushroom". Mycologia. 70 (2): 385–396. doi:10.2307/3759037. JSTOR 3759037. PMID 566852.
  7. ^ Stamets, Paul (1996). Psilocybin mushrooms of the world: an identification guide. Berkeley, Calif: Ten Speed Press. ISBN 0-89815-839-7.