Poisonous Mushrooms Identifying dangerous species in the Pacific Northwest and what to do if someone eats one

Most mushrooms won’t kill you. Of the thousands of species in the Pacific Northwest, only a handful contain toxins capable of causing serious organ damage or death. But those few species are responsible for nearly all fatal mushroom poisonings worldwide — and they grow right here in Western Washington and Oregon.

This page covers two things: which PNW mushrooms are genuinely dangerous, and exactly what to do if you suspect someone has eaten one. Knowing both could save a life.

Amatoxin-Containing Mushrooms: The Deadly Ones

Amatoxins cause delayed liver and kidney failure. These are the species responsible for nearly all mushroom fatalities. They share a key trait: symptoms don’t appear for 6–12 hours after eating, by which time significant organ damage may have already begun.

Death Cap

Amanita phalloides

Responsible for more mushroom deaths worldwide than any other species. Now established in the PNW, especially in urban areas under imported oaks and other landscape trees.

• Greenish-yellow to olive cap (can appear pale or white)
• White, free gills (not attached to stem)
• Bulbous base with a cup-like sac (volva) — often buried underground
• White ring (annulus) on the upper stem
• No distinctive smell when fresh

Deadly
Amatoxin

Destroying Angel

Amanita ocreata / A. amerivirosa

Entirely white and easily mistaken for edible species like meadow mushrooms or puffballs by beginners. Found in PNW forests and woodland edges, especially with oaks.

• Pure white cap, gills, stem, and base
• Free gills (not attached to stem)
• Bulbous base with volva sac
• Ring on upper stem (may disappear with age)
• No warts on cap (unlike A. muscaria)

Deadly
Amatoxin

Deadly Lepiota

Lepiota subincarnata / L. brunneoincarnata

Small, easily overlooked mushrooms that contain lethal doses of amatoxins. Found in gardens, mulched beds, and disturbed ground — places where people might casually pick mushrooms.

• Small (cap 2–5 cm) with pinkish-brown to reddish-brown scales
• White, free gills
• Ring on stem (may be fragile or fibrous)
• Often fruity or unpleasant smell
• Grows in gardens, greenhouses, and urban landscaping

Deadly
Amatoxin

Deadly Galerina

Galerina marginata

A small brown mushroom that grows on decaying wood — sometimes mistaken for edible species or psychoactive Psilocybe. Common throughout PNW forests year-round.

• Small brown cap (2–5 cm), smooth and slightly sticky when wet
• Brownish gills, attached to stem
• Ring on stem (may be faint or disappear)
• Grows on rotting wood (logs, stumps, buried wood)
• Can fruit alongside edible species on the same log

Deadly
Amatoxin

Other Toxic Mushrooms in the PNW

The amatoxin species above are the most dangerous, but other PNW mushrooms can cause significant illness:

• Panther Cap (Amanita pantherina) — Contains ibotenic acid and muscimol. Common in PNW conifer forests. Causes delirium, seizures, and coma. Looks like a brown version of the fly agaric. Distinguished by white warts on a brown cap, white gills, and a bulbous base with a distinct rim.
• Smith’s Amanita (Amanita smithiana) — Causes kidney failure. Large, white, and found under conifers. Has been mistaken for matsutake by foragers.
• Angel Wings (Pleurocybella porrigens) — White shelf fungus on conifer logs. Linked to fatal encephalopathy in people with pre-existing kidney conditions, particularly in Japan. Best avoided despite historical use as an edible.
• Jack O’Lantern (Omphalotus olearius) — Orange shelf fungus sometimes confused with chanterelles. Causes severe GI distress but not organ damage.
• False Morels (Gyromitra esculenta) — Contains gyromitrin, which converts to a hydrazine compound. Can cause liver failure. Brain-like cap, not honeycomb-patterned like true morels.

How to Avoid Poisonous Mushrooms

There are no shortcuts or folk tests that reliably separate edible from poisonous species. Silver spoons, peeling the cap, and animal behavior are all myths. What actually works:

• Learn specific species, not general rules. Know the exact features of each species you plan to eat. Don’t eat anything based on “it looks like” a photo.
• Always check the base. Dig up the entire mushroom. The volva (sac) at the base of deadly Amanita is the single most important safety feature to look for — and it’s often hidden underground.
• Take a class. In-person instruction from an experienced mycologist is the fastest way to build safe identification skills. Salish Mushrooms classes cover dangerous lookalikes alongside edible species.
• Start with distinctive species. Chanterelles, hedgehogs, oyster mushrooms, and chicken of the woods have few dangerous lookalikes compared to “little brown mushrooms” or white-gilled ground mushrooms.
• When in doubt, don’t eat it. No mushroom meal is worth the risk. If you can’t confidently identify a mushroom to species, leave it.

Resources

• Poison Control (poison.org)
  Call 1-800-222-1222 for immediate poisoning guidance — 24/7
• Mushroom Poisoning Identification (Facebook)
  Emergency ID group monitored by toxicologists and experienced identifiers
• PNW Mushroom ID (Facebook)
  Pacific Northwest regional identification help
• NAMA: Mushroom Poisoning in Dogs and Cats
  North American Mycological Association guide for pet owners
• Bay Area Mycological Society: Amatoxins
  Detailed overview of amatoxin chemistry and treatment
• NAMA Poisoning Reports Summary (2018–2020)
  Data on mushroom poisoning incidents across North America