Panaeolus subbalteus also known as Panaeolus cinctulus or Pan. venenosus, is believed to be the most common psilocybin-containing mushroom to grow in California and the most common of the Panaeolus genus to grow in Europe.
Its fimicole nature has most probably helped it spread worldwide through manure it had colonized, making the specie also present in the Americas and in Asia where the Japonese refer to it as the laughing mushroom.
In the early 1900s it inherited of the name weed Panaeolus because it was always finding its way inside the bed cultures of grocery-store mushroom Agaricus bisporus. Its known hallucinogenic properties forced mushroom farmers to carefully weed them out from the edible mushrooms. It was actually through yet another accidental intoxication that his psychoactivity was discovered.
It thrives in well-manured grassy soils and has a symbiotic relationship with horse dung. Folk rumors report the Germanic people, in honor of the horse, sacred animal of Wotan the Germanic god of extasy, would add it to their beer or meals. This classic Druid mushroom was commonly called by the Germans “dunkelrandiger düngerling” translating to the “dark-banded dung mushroom”.
Today, it is believed to gain popularity through the resurgence of pagan festivals in middle and northern Europe.