In the late 1930s the first two of the many species of sacred Mexican mushrooms were collected and associated with a modern mushroom ceremony. Subsequent fieldwork has resulted in the discovery of some two dozen species. The most important belong to the genus Psilocybe , twelve of which have been reported, not including Stropharia cubensis , sometimes considered a Psilocybe . The most important species appear to be Psilocybe mexicana and P. hoogshagenii . The present center of intensive use of the sacred mushrooms is among the Mazatec.
Mushrooms vary in abundance from year to year and at different seasons.
And certain mushrooms are used for specific purposes. This means that each ethnobotanical expedition may not expect to find the same assortment of species employed at one time, even in the same locality and by the same people. The probability that more species will be found in use is far from remote. Chemical studies have indicated that psilocybine and, to a lesser extent, psilocine are present in many of the species of the several genera associated with the Mexican ceremony. In fact, these compounds have been isolated from many species of Psilocybe and other genera in widely separated parts of the world, although the evidence available suggests that only in Mexico are psilocybine-containing mushrooms at present utilized in native ceremonies.