Psilocybe subaeruginosa is a potent species of psychedelic mushroom belonging to the family Hymenogastraceae. This species is native to Australia and New Zealand and is known for its high concentrations of psilocybin and psilocin, the primary psychoactive compounds responsible for its strong effects.

Psilocybe subaeruginosa typically grows in wood chips, mulch, or in disturbed areas rich in woody debris, particularly in eucalyptus forests. It is most commonly found during the cooler, wetter months of late autumn to early winter.

Morphologically, Psilocybe subaeruginosa features a conical to convex cap, which can flatten with age. The cap is often caramel to chestnut brown, sometimes with a blue-green hue, especially when bruised. The gills are attached, turning from light brown to dark purple-brown as the spores mature. The stem is usually thick, white to pale brown, and bruises blue when handled, a common trait among many Psilocybe species.