Wild Species Bluing ✓ Potency: ★★★☆☆

Psilocybe baeocystis

Common name: Bottle Cap, Knobby Tops

Field Identification

Cap1.5–5.5cm; convex with a distinctive acute umbo (knob) — giving the 'knobby tops' common name; olive-brown to steel-blue; hygrophanous; smooth and slightly viscid when moist
GillsAdnate; gray-white becoming dark chocolate-brown
Stem5–7cm; pale yellowish-white; fragile; straight; silky; mycelial mat at base; blueing when bruised or dried
Spore PrintDark purplish-brown
HabitatDouglas fir bark, wood chips, peat moss, grassy areas with wood debris; common in landscaped urban areas with wood chip mulch
DistributionPacific Northwest USA (Oregon, Washington, western British Columbia)
SeasonSeptember–December

Key Identification Feature

The acute central umbo (knob) on the cap is the most distinctive visible feature among Pacific Northwest Psilocybe species. Olive to steel-blue coloration and wood chip urban habitat further distinguish it. One of the more reliably identifiable PNW species.

⚠ Dangerous Lookalikes

Galerina marginata (DEADLY — wood debris habitat; ring present; rusty spore print), Psilocybe cyanescens (wavy cap; no knob; higher potency), Hypholoma fasciculare (no bluing; sulfur yellow cap; bitter taste)

Notes

Psilocybe baeocystis was one of the key Pacific Northwest species identified by Andrew Weil and documented in early psychedelic literature. The species name 'baeocystis' references the unique cystidia (cells) on its gill surface. Its tolerance for disturbed urban environments (bark, wood chips in parks and landscaping) makes it one of the more commonly encountered Pacific Northwest psychoactive species outside of forests.

Legal Status Warning Psilocybin-containing mushrooms are controlled substances in most jurisdictions. This guide is for educational purposes only. Wild foraging for psilocybin mushrooms may be illegal in your location. Never consume wild mushrooms without positive identification from an expert mycologist — misidentification can be fatal.

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