In interviewing persons who have ingested hallucinogenic 
mushrooms, it is important, therefore, to determine the source 
of the material. Was it collected in the field or obtained from 
someone who collected it? If not, it may not contain psilocybin. 
A useful question to ask is how long the effects lasted. If 
symptoms were felt beyond six hours, the active compound 
was almost certainly LSD. If symptoms dissipated by six 
hours, psilocybin is a possibility, but low doses of LSD may 
also fade early, especially if the user expects the effects of 
mushrooms to be short. In studying psychoactive drugs, we 
see repeatedly that psychological expectation (set) may be the 
single most important factor determining individual reactions, 
even over-riding direct pharmacological action. (A spectacular 
example is variation in response to Amanita pantherina, to be 
discussed below). This fact may explain why many persons 
who ingest false psilocybin mushrooms feel that their experi- 
ences are qualitatively different from anything that they have 
felt on LSD. 
In the Pacific Northwest, genuine psilocybin mushrooms are 
small and inconspicuous, typically growing in open, grassy 
places, such as lawns and fields, often in association with cow 
manure. A few woodland species also occur. These mush- 
rooms do not call attention to themselves by their size, colors, 
or growth habits, and, as their caps are quite thin, they have 
never been pursued by hunters of edible mushrooms. The two 
genera in use are Psilocybe and Panaeolus. Until the discov- 
eries in Oaxaca, no one cared much about these fungal groups, 
and, consequently, relatively little information is to be found 
on them in the scientific literature. And because they have been 
of so little interest to collectors, there is no good body of data 
on their field characteristics. 
Many amateur mushroom hunters read descriptions of 
Psilocybe and Panaeolus in guide books, then attempt to find 
them in cow pastures. Anyone who has hunted in this way 
knows how frustrating it is to meet the bewildering array of 
little bbown mushrooms that come up in pastures in the fall. It is 
quite possible that some of them are undescribed species, 
because, until recently, experts often ignored these groups of 
inconspicuous mushrooms. 
Psilocybe, the genus with the greatest number of active 
species, has purple-brown spores and a number of characteris- 
tic anatomical features visible under the microscope. Not all 
species of Psilocybe contain psilocybin, but those that do seem 
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