Psilocybe ovoideocystidiata is a psilocybin mushroom in the section Stuntzae, having psilocybin and/or psilocin as main active compounds. It is closely related to P. subaeruginascens from Indonesia, P. septentrionalis from Japan, and P. wayanadensis from India. This mushroom was first documented by Richard V. Gaines in Montgomery County in June 2003. Although it is sometimes confused with Psilocybe caerulipes, it can be distinguished by its rhomboid spores, larger stature, earlier fruiting season and membranous annulus.