Psilocybe liniformans is a small, brown mushroom in the psilocybin-containing genus Psilocybe, growing in grassy habitats including lawns, pastures, and roadsides in Europe and North America. It produces a blueing reaction when damaged, indicating the presence of psychoactive compounds. Classified as Endangered, this species faces threats from habitat loss and the degradation of unimproved grassland habitats.