Psilocybe aztecorum

Psilocybe aztecorum is a species of psilocybin mushroom in the family Hymenogastraceae. Known only from central Mexico, the fungus grows on decomposing woody debris and is found in mountainous areas at elevations of 3,200 to 4,000 m (10,500 to 13,100 ft), typically in meadows or open, grassy forests associated with Hartweg's pine (Pinus hartwegii). The mushrooms have convex to bell-shaped caps 1.5–2 cm (0.6–0.8 in) in diameter, atop slender cylindrical stems that are up to 7.5 cm (3.0 in) long. The color of the caps changes with variations in hydration, ranging from dark chestnut brown to straw yellow or whitish when dry. The base of the stem is densely covered with conspicuous white rhizomorphs, a characteristic uncommon amongst Psilocybe species.