Panaeolus castaneifolius
CAP: 1-3(4)cm, distinctly bellshaped at first, soon nearly hemispheric, then convex, and becoming broadly convex in age (never fully expanding), margin incurved when young; hygrophanous, dark smoky gray, drying to more straw yellow or pale ochraceous, remaining more reddish brown at top and smoky brownish along margin; sometimes finely wrinkled, margin not appendiculate, and slightly striate, (Stamets), 1-4cm, convex, never fully expanding, margin incurved when young; hygrophanous dark cinnamon drying to pinkish buff; smooth, often wrinkled, margin even when young, translucent striate when moist, no veil remnants, (PNW keys)
FLESH: thick, firm, (PNW keys)
GILLS: adnate to adnexed, close, thin; pallid, becoming dark purplish gray-black, (Stamets), adnate to adnexed, subclose; pallid, darkening to chestnut with age, edge white, (PNW keys)
STEM: 4-6(7.5)cm x 0.3-0.4(0.6)cm, equal to more narrow toward base, hollow, brittle; grayish to ochraceous or tan at the base; pruinose, slightly striate, (Stamets), 4.5-7cm x 0.4-0.6cm, straight and slightly tapering toward the base, base not enlarged, stem hollow, cartilaginous; colored as cap but may be lighter near the top when young; pruinose, no veil remnants, top slightly striate, (PNW keys)
VEIL: no veil, remnants on margin
EDIBILITY: sometimes slightly hallucinogenic
HABITAT: gregarious in grassy places (Stamets)
SPORES: dark purplish gray-black (Stamets) 12-15 x 7-9.5 microns, presumably elliptic, finely rough, presumably with germ pore, cheilocystidia 20-28(35) x 7-10 microns, pleurocystidia few or absent, not projecting beyond plane of basidia, (Stamets)
NAME ORIGIN: means ' with gills the color of chestnuts'
SIMILAR: foenisecii (also in grass) but castaneifolius has slightly thicker (0.3-0.6cm) stem without enlarged base, purple-black gills, purple black spores
SOURCES: Stamets*, PNW keys
NOTES: features include bellshaped to nearly hemispheric cap, some but not all collections contain psilocybin; rare in PNW
This mushroom is often mistaken for Panaeolus foenisecii, and is distinguished by the dark purplish grayish blackish spore deposit and the gill color.
Photo by Michaeil Beug
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