Every fall, once the rain settles in, small caramel-colored mushrooms with rippled edges push up through the wood chips in Seattle's planting strips, parks and office landscaping. Many of them are Psilocybe cyanescens, the wavy cap, a psilocybin species that thrives in exactly the kind of wood-chip mulch cities spread every year. Some of them, in the same beds, aren't.
The lookalike
Galerina marginata is a small brown mushroom that grows on rotting wood and wood chips and is common across the Pacific Northwest. It contains amatoxins, the toxins responsible for most fatal mushroom poisonings worldwide, and they survive cooking and drying. The two are distinguished by a combination of features, including spore print color (purple-brown for wavy caps, rusty brown for Galerina) and the stem, which darkens on Galerina rather than bruising blue, according to the University of British Columbia's Beaty Biodiversity Museum. But features fade in old or waterlogged mushrooms, and both can grow in the same patch, so a single handful can hold both.
The problem runs through the region's psilocybin species. Psilocybe stuntzii, a small brown mushroom first collected on the University of Washington campus and described in 1976, is another one field guides warn can be mistaken for Galerina.
Why amatoxin poisoning is so dangerous
Most poisonous mushrooms make people sick quickly. Amatoxins don't. The Puget Sound Mycological Society describes a latent period of usually 8 to 12 hours before severe vomiting and diarrhea begin, followed later by liver damage. People often seem to recover for a day before liver and kidney failure set in. By the time someone feels sick, the toxin has already been absorbed, which is why early treatment matters so much.
The risk isn't theoretical on the West Coast. In California, a surge of death cap poisonings in the 2025–26 season had put 35 people in the hospital and killed three by early January 2026, according to a state health alert reported by the California Medical Association. Death caps have also been found in Seattle, on the UW campus in 2019.
What to do
"Unless you're a mushroom expert, it's best to avoid wild mushrooms altogether," the Washington Poison Center advises. If someone may have eaten a mushroom that wasn't positively identified:
- Call the Washington Poison Center at 1-800-222-1222, free and 24 hours a day. Don't wait for symptoms.
- Keep any leftover mushroom, or photograph it from every angle; the center may ask for pictures to help identify it.
- Call 911 for difficulty breathing, seizures or loss of consciousness.
If you want to learn what's growing around you, the Puget Sound Mycological Society's Wild Mushroom Show this weekend in Shoreline puts identified poisonous and edible species side by side.
A legal note
Picking psilocybin mushrooms is possessing a controlled substance under Washington law, whether they came from a grow tent or a parking-lot planter. Seattle's 2021 resolution makes personal possession a lowest police priority; it doesn't make it legal. Our guide to wild psilocybin mushrooms in Washington has more on the species and their lookalikes.
Sources
- UBC Beaty Biodiversity Museum, Psilocybe cyanescens
- UBC Beaty Biodiversity Museum, Galerina marginata
- Washington Poison Center, "A mushroom PSA" (2025)
- Puget Sound Mycological Society, mushroom poisoning
- California Medical Association, CDPH alert on death cap poisonings (Jan. 2026)
- KIRO 7, UW warns of death caps on campus (Oct. 2019)
Last checked against the sources above on Oct 20, 2026. Spotted something out of date? Tell us.