Panaeolus subbalteatus

Panaeolus subbalteatus, also known as Panaeolus cinctulus is a very common hallucinogenic mushroom which is widely distributed. The mushroom is a coprophiliac (dung-inhabiting) species which also grows well in other habitats including fertilized lawns, haystacks, compost heaps, and riding stables. It grows abundantly year round after rain nearly everywhere and is common in Oregon, Washington and Northern California but also known to occur in all 50 states, Great Britain, Europe, Russia, Asia, Australia, Mexico, Central and South America and British Columbia. According to David Arora, Panaeolus subbalteatus is the most common psilocybin mushroom in California.

During the early part of the 20th century this species was often referred to as the "weed Panaeolus" because it was a common occurrence in beds of the commercially grown grocery store mushroom Agaricus bisporus. Because of its intoxicating properties the mushroom farmers had to weed it out from the edible mushrooms.

Although not specifically scheduled in the United States, psilocybin containing mushrooms are considered "containers" of a scheduled substance, and their usage and possession is illegal in most states.