How to identify Psilocybe cubensis — cap, gills, purple-black spore print, and blue bruising — plus the look-alikes that send foragers to the hospital.
Psilocybe cubensis is a psilocybin-containing mushroom that grows on dung and rich soil in warm, humid regions. It is the best-known and most widely cultivated psychedelic mushroom, and nearly every named "strain" sold as spores — Golden Teacher, B+, Penis Envy — is a cultivated form of this one species. In the wild it appears across the Gulf Coast and southeastern United States, Mexico, Central and South America, Southeast Asia, and northern Australia.
Because it is the default "magic mushroom," people often assume it is easy to identify. It is more distinctive than most psilocybes, but the genuinely dangerous mistake is not confusing it with another psychoactive species — it is confusing a small brown mushroom for a deadly amatoxin one. That is why this guide leads with the spore print.
The cap is 1.5 to 8 centimetres wide. It starts conic to bell-shaped and opens to broadly convex or nearly flat with age, often keeping a low central bump (umbo). Colour is reddish-cinnamon to golden-brown, usually paler toward the margin, and it fades as it dries because the cap is hygrophanous. The surface is smooth and slightly sticky when wet.
Gills are attached to the stem and crowded. They start pale grey-brown and darken to deep purple-brown or nearly black as the spores mature, often looking mottled. This dark, purple-toned gill colour is a direct reflection of the spore colour — and the first visual cue that separates cubensis from the rusty-gilled deadly look-alikes.
Cut the stem off, set the cap gill-side-down on white paper for two to four hours, and read the colour that drops. Psilocybe cubensis leaves a dark purple-brown to purple-black spore print. A rust-brown or cinnamon print rules the whole Psilocybe genus out and points toward a potentially deadly mushroom. The North American Mycological Association (NAMA) treats the spore print as the single most reliable check for exactly this reason.
Handle or cut the flesh and watch the damaged area. Psilocybe cubensis bruises blue to blue-green within minutes, because damaged psilocin oxidizes into a blue pigment. Blueing is a useful positive signal, but it is not a stand-alone safety test: a few non-psilocybin mushrooms also blue, and the absence of blueing does not make a mushroom safe. Pair it with the spore print, never rely on it alone.
The stem is 4 to 15 centimetres tall, white to yellowish, dry, and thickens slightly toward the base. It carries a persistent membranous ring (annulus) that usually turns purple-black as falling spores dust it. The stem also bruises bluish where handled. A well-formed dark-dusted ring plus blue bruising plus a purple print is a strong, coherent picture.
Psilocybe cubensis is dung-loving. It fruits directly on cattle and water-buffalo dung, and on the rich, well-manured pasture soil around it, in warm and humid weather. It does not grow on wood. That single fact separates it from the wood-cluster look-alikes such as Galerina and wood-loving Psilocybe, though habitat alone is never a substitute for a spore print.
Two very different categories of look-alike matter, and they carry very different stakes. One group is other dung and grassland mushrooms that are merely not what you wanted. The other is the small brown amatoxin mushrooms that can kill you. Always resolve the second group first.
| Look-alike | How it differs from cubensis | Risk |
|---|---|---|
| Panaeolus / Panaeolina (mottlegills) | Also on dung; black spore print, strongly mottled gills, no ring, no blue bruising in the non-active ones | Some active, some inert — easy to mistake for cubensis |
| Protostropharia semiglobata (dung roundhead) | On dung; sticky yellowish hemispheric cap, purple-brown print, but no meaningful blue bruising | Not psychoactive; a common disappointment, not a danger |
| Galerina marginata | Rusty-brown spore print, grows in clusters on wood, no blue bruising | Deadly — amatoxins |
| Conocybe filaris (Pholiotina rugosa) | Rust-brown spore print, small conic cap, lawn/moss habitat, ringed stem, no blueing | Deadly — amatoxins |
| Gymnopilus (big laughing gym) | Rusty-orange spore print, bitter, grows on wood, brighter orange tones | Some active, unpleasant; rusty print rules out cubensis |
The rule that ties the table together: a rusty or cinnamon spore print is a hard stop. It cannot be a Psilocybe, and it may be a deadly amatoxin mushroom. For the full reasoning on why experienced foragers still die making this mistake, see the identification-safety guide.
Identifying a mushroom correctly does not make picking it legal or safe. Psilocybin is federally Schedule I, wild harvesting is illegal in most states, and even a correct identification carries dose uncertainty. The regulated programs in Oregon and Colorado exist so adults can access dose-verified, professionally identified psilocybin without foraging. See:
Identify Psilocybe cubensis by four features together: a golden-brown hygrophanous cap, crowded gills that darken to purple-black, a persistent ring on the stem, and blue bruising where the flesh is damaged. Confirm with a spore print — cubensis drops a purple-black print. Never rely on a single feature.
Dark purple-brown to purple-black. Every Psilocybe species drops a purple-toned print. A rusty-brown or cinnamon print means the mushroom is not a Psilocybe and may be a deadly amatoxin species such as Galerina or Conocybe.
Yes. Psilocybe cubensis bruises blue to blue-green within minutes where the stem or cap is handled or cut, because damaged psilocin oxidizes to a blue pigment. Blueing supports an identification but is not a stand-alone safety test — a few other mushrooms also blue.
The deadly ones are the amatoxin mushrooms Galerina marginata and Conocybe filaris (Pholiotina rugosa). Both are small and brown with a rust-brown spore print and no blue bruising. Panaeolus, Protostropharia, and Gymnopilus species are non-deadly look-alikes. A rusty spore print rules out cubensis and flags possible danger.
On cattle and water-buffalo dung and rich pasture soil in warm, humid climates. In the United States it is found mainly along the Gulf Coast and the Southeast. It grows on dung and manured ground, not on wood — a mushroom growing in clusters on a log is not cubensis.
In most of the United States, no. Psilocybin is federally Schedule I, and wild picking or possession is illegal in most states. Legal adult use exists only through Oregon's Measure 109 and Colorado's Prop 122 service centers. See our state-by-state legality guide.
Get mushroom identification research & policy updates
New trials, FDA decisions, and legal changes for mushroom identification — delivered when they happen.
Suggest a tool, topic, or improvement that would make this site more useful.