Pileus (cap): The cap is 2%u201313 cm, conical to convex, and very rarely expanding to plane in age. The margin wavy sometimes with an acute papilla or mamilla, usually umbonate or with a depressed center. In young specimens the margin has a scalloped edge which sometimes curls upwards as the mushroom matures. The cap is yellowish brown to tan, fading to cream-yellow then brown and finally black through age. The flesh is originally white but soon changes to a cyan blue, then quickly to black.
Lamellae (Gills): Psilocybe zapotecorum gills are a cream color when young and violet brown in age, with an attachment that is sinuate or adnate, and sometimes subdecurrent.
Stipe (stem): The stipe is 3%u201326 cm long, and 0.5%u20131 cm thick. It is central, flexuous, cylindric or slightly flattened, and hollow. It can be white to grey, turning yellowish, blue, and black in age. The entire stem is covered with many white scales which are more pronounced in the lower part of the stipe. The partial veil is white and arachnoid, disappearing in age. Often a long pseudorrhiza can be found attached the base of the stipe. Strongly bruising blue then black where damaged.
Microscopic features: The spores are dark violet brown, oblong to ellipsoid to subrhomboid, and thin-walled. They are 7 by 4 um.
Season: Spring, summer, and fall.
Habitat and Distribution: It is found near rivers, creaks and ravines, sometimes growing directly from steep mossy ravine walls. Psilocybe zapotecorum is also found in humid and shadowed places in mesophytic forests, oak-and-pine forests, or cloud forests. Psilocybe zapotecorum is often found in subtropical forests containing Alnus sp., Magnolia sp., Fraxinus sp., Quercus sp., large pines, and blackberry bushes. Psilocybe zapotecorum grows in Argentina, Brazil, Chile, Colombia, Mexico, and Peru.
Growth Habit: Psilocybe zapotecorum grows solitarily or gregariously.
Bruising: Bruising where damaged.
Other Notes: "Rediscovered" and named by French mycologist Roger Heim, this mushroom is one of the shaman's favorites, typically yielding up to ca. .85% psilocybin and up to ca. .25% psilocin. Its preferred habitat is muddy soils and marshy areas; also rich, dark soils of deciduous forests where it can be found fruiting throughout summer in clusters or groups.