Panaeolus bisporus, also known as Copelandia bisporus is a rare and widely distributed little brown mushroom that bruises blue and contains the hallucinogen psilocybin. This mushroom is similar macroscopically to Panaeolus tropicalis, Panaeolus cambodginiensis and Panaeolus cyanescens, but can be differentiated using a microscope by its two spored basidia.