“Psilocybe baeocystis is named because of its distinctive rippled cap, with baeo-cystis translating to “small-bladder,” something that when fresh resembles the fungus. Under the aliases of “bottle caps,” “knobby tops,” “blue bells” or “olive caps,” all references to the various cap characteristics are found more commonly. Together with the wavy ripples, the cap stains easily from a chestnut-brown, olive-green to a vivid dark blue when handled or aged.
A relative oddity with respect to this species is that its potency when fresh is markedly higher, typically declining to at least half with drying. This may be due to the very high levels of a psychoactive psilocybin precursor, baeocystin.