Psilocybe cyanofibrillosa also known as Rhododendron Psilocybe and Blue-Haired Psilocybe is a psilocybin mushroom of the Agaricales family having psilocybin and psilocin as main active compounds. First documented in 1980 in the Pacific Northwest, it is relatively uncommon and can be distinguished from other closely related species by its smaller spores and forking cheilocystidia.Psilocybe cyanescens also has forking cheilocystidia, but less often than Psilocybe cyanofibrillosa. Psilocybe cyanofibrillosa is also distinguished from Psilocybe cyanescens by an absence of pleurocystidia. The name of this species refers to the fibrils on the stipe that turn bluish in age, or when handled.