Variation of psilocybin and psilocin levels with repeated flushes (harvests) of mature sporocarps of Psilocybe cubensis (Earle) Singer.
Analysis of Psilocybe cubensis (Earle) Singer grown in controlled culture showed that the level of psilocin was generally zero in the first (or sometimes even the second) fruiting of the mushroom from a given culture and that the level reached a maximum by the fourth flush. The level of psilocybin, which was nearly always at least twice the level of psilocin, showed no upward or downward trend as fruiting progressed, but was variable over a factor of four. Samples obtained from outside sources had psilocybin levels varying by over a factor of ten from one collection to the next.
Psilocybin and psilocin levels in twenty species from seven genera of wild mushrooms in the Pacific Northwest, U.S.A.
The analysis of twenty species from seven genera of Pacific Northwest mushrooms revealed psilocybin (and in some cases psilocin as well) in seven species from three genera. The species found to contain psilocybin (and psilocin) varied from one collection to another by more than a factor of seven in amount present. Total psilocybin and psilocin levels in species known to be in use for recreational and entheogenic purposes varied from 0.1% by dry weight up to a high of nearly 2% by dry weight.
The nature of the microbial stimulus affecting sporophore formation in Agaricus bisporus (Lange) Sing
SUMMARY 
 
An apparatus is described in which pure cultures of Agaricus bisporus were maintained on composted media in filtered atmospheres free from (a) noxious concentrations of carbon dioxide, and (b) contaminating microorganisms. When grown on compost alone, cultures of A. bisporus did not produce sporophores. Their formation was however stimulated by a covering layer of an unsterilized mixture of peat and chalk (=‘casing’ soil). Autoclaving or fumigating ‘casing’ with propylene oxide decreased populations of contaminating bacteria and prevented sporophore formation. 
 
 
 
Populations of micro-organisms isolated from unsterile ‘casing’ contained bacteria which when added to pure cultures of A. bisporus stimulated fruit-body formation. Numbers of these stimulators increased when cultured on a carbon-free liquid medium exposed to atmospheres with ethanol, ethyl acetate and acetone or containing the volatile metabolites of A. bisporus. The ability to utilize these volatile chemicals was exploited in a selective technique for isolating sporophore stimulators where aqueous suspensions of mixed bacterial populations were exposed to atmospheres of these materials for 5 days, before aliquots were added to agar media subsequently gelled. 
 
 
 
The stimulatory bacteria were identified as, or closely related to, Pseudomonas putida.