Banded Mottlegill

The cap is 1.5–6 centimetres (1⁄2–2+1⁄2 in) wide, hemispherical to convex when young to broadly umbonate or plane in age, smooth, hygrophanous, striking cinnamon-brown when moist, soot-black when wet which disappears as the mushroom completely dries out. The outer band is usually darker. The flesh is thin and brownish. The gills are close, adnate to adnexed, cream-colored when young, later mottled dingy brown then to soot-black. The gill edges are white and slightly fringed, but turn blackish when fully mature. The spore print is black. The stipe is 4–10 cm long, 1–10 mm thick, equal or tapered at the ends, reddish brown or covered by whitish powder, hollow, no veil remnants, longitudinally white-fibrillose, striate at the apex or twisting vertically down the entire length of the stipe. The stem base and mycelium occasionally stain blue. The taste is farinaceous (like flour) when fresh, saliferous (salty) when dried. The odor is slightly farinaceous.

Microscopic features. The spores are 11–14 x 7.5–9.5 μm, smooth, elliptical to rhomboid in face view, thick-walled, elliptical in side view.

Similar species. Morphologically, P. cinctulus can be easily confused with other species of psilocybin mushrooms. They have a resemblance to P. fimicola and prefer the same habitats, but the latter species has sulphidia on the gill faces. It can also resemble P. foenisecii and P. olivaceus.

Panaeolus cinctulus is a cosmopolitan species that grows solitary to gregarious to cespitose (densely clumped) on compost piles, well-fertilized lawns and gardens, and, rarely, directly on horse dung. It grows from spring to fall, abundantly after rain. It can be found in many regions, including: Africa (South Africa), Austria, Canada (Alberta, British Columbia, New Brunswick, Prince Edward Island, Ontario, Quebec, Nova Scotia), Denmark, Finland, France, Germany, Great Britain, Guadeloupe, Estonia, Iceland, India, Ireland, Italy, South Korea, Japan, Mexico, New Guinea, New Zealand, Norway, Philippines, Russia, Romania , Slovenia, South America (Argentina, Chile, Brazil) and the United States (common in Oregon, Alaska, Washington, and both northern and southern California, but known to occur in all 50 states). According to American mycologist David Arora, P. cinctulus is the most common psilocybin mushroom in California. It has also been sighted in Melbourne, Australia, Central Queensland, Australia Belgium and the Czech Republic.

The descriptor subbalteatus comes from the Latin words sub ('somewhat') and balteat ('girdled'), a reference to the dark outer band of the cap.