Unable to locate this species in the field, botanist Roger Heim and mycologist Rolf Singer based their descriptions of this mushroom on dried specimens purchased from Matlatzinca Indians in the marketplace of Tenango del Valle, in the Nevado de Toluca region of the state of Mexico. In 1958 Roger Heim described this fungus as Psilocybe wassonii, but without any Latin designation; Rolf Singer and Alexander Hanchett Smith described it in the same year as Psilocybe muliercula (muliercula = little women). Both descriptions reported this fungus growing in Pinus forests surrounding the town of Tenango del Valle. However, after several expeditions to the area, Mexican mycologist Gaston Guzman located it 10 kilometers from Tenango del Valle in an Abies forest on the slopes of the Nevado de Toluca.