Panaeolus cinctulus, syn. Panaeolus subbalteatus, commonly known as the banded mottlegill, weed Panaeolus or subbs is a very common, widely distributed psilocybin mushroom. According to American naturalist and mycologist David Arora, Panaeolus cinctulus is the most common psilocybin mushroom in California.
During the early 1900s, these species were referred to as the "weed Panaeolus" because they were commonly found in beds of the commercially grown, grocery-store mushroom Agaricus bisporus. Mushroom farmers had to weed it out from the edible mushrooms because of its hallucinogenic properties.