|gills on hymenium|
|cap is convex or conical|
|hymenium is adnate or sinuate|
|stipe is bare|
|spore print is purple-brown|
|ecology is saprotrophic|
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.
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. 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.
This species closely resembles subtropical Psilocybe aztecorum and Psilocybe quebecensis, which also have caps that bleach in color to white when dry.
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, and a few years later, Leung and Paul would report the related compound baeocystin, isolated from saprophytic culture, as well as the desmethyl metabolite norbaeocystin. Beug and Bigwood (1981) also reported on the concentrations of these compounds in Psilocybe baeocystis using reverse-phase HPLC and thin-layer chromatography. 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.