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‘Shrooms Are Blooming, Danger Is Looming

Photo: EBRPD

From the East Bay Regional Park District:

Oakland, CA – Mushrooms are an ecologically important part of our parklands and can look beautiful – but some of them contain dangerous toxins. Each year, mushrooms proliferate after the first sustained rains of the season. The death cap (Amanita phalloides) and Western destroying angel (Amanita ocreata) are two of the world’s most toxic mushrooms, and both can be found in East Bay Regional Parks during the rainy season.

The death cap and Western destroying angel mushrooms contain amatoxins, molecules that are deadly to many animals. Symptoms may not appear until up to 12 hours after consumption, beginning as severe gastrointestinal distress and progressing to liver and kidney failure if treatment is not sought immediately.

East Bay Regional Park District Naturalist Trent Pearce documents and teaches about fungi in the Bay Area. “Both of these mushrooms can be lethal to humans and pets if consumed,” Pearce warns. “They are mainly associated with oak trees and can be found growing anywhere oak roots are present.”

The death cap is a medium to large mushroom that typically has a greenish-gray cap, white gills, a white ring around the stem, and a large white sac at the base of the stem. Although the death cap is mainly associated with oak trees, it has been found growing with other hardwoods. It was accidentally introduced to North America on the roots of European cork oaks and is now slowly colonizing the West Coast. The death cap is not native to California.

The Western destroying angel is a medium to large mushroom that usually has a creamy white cap, white gills, a white ring around the stem that can disappear with age, and a thin white sac at the base. It fruits from late winter into spring. It is associated exclusively with oaks. Unlike the death cap, it is a native California mushroom.

“The Park District urges the public to be safe and knowledgeable about toxic mushrooms when encountering them in the parks,” said East Bay Regional Park District Public Information Supervisor Dave Mason. “Collecting any mushrooms in East Bay Regional Parks is not allowed.”

The death cap and Western destroying angel can also be dangerous for pets.

“Dog owners should keep a close watch on their dogs during the winter months,” said Mason. “Pet owners should contact a veterinarian immediately if they suspect their pet may have eaten a toxic mushroom.”

While the death cap and western destroying angel mushrooms are responsible for most cases of mushroom poisonings in California, deadly toxins can also be found in Galerina and Lepiota mushroom species, which also occur in the Bay Area.

See also:

Beware Toxic Mushrooms

Annual Fungus Fair to be Held Virtually

This year, the annual Tilden Fungus Fair will be held virtually on Saturday, January 16, 2021 from 10 am to 3 pm. The event will be available via Zoom Webinar and live streamed on FacebookInstagram and YouTube. Tune in for presentations from mushroom experts, a live mushroom cooking demonstration, reviews of mushroom field guides, trivia, and more.


  1. The shrooms have been sporadic but plentiful this year. In addition to the temptingly clean white ones, I have had large brown ones that appear to have been chewed by somethin…a rodent perhaps? Currently I have little cuplike eruptions that barely disturb the surface. I don’t think they are puff balls but they are similar in appearance, erupting at the top. I have pretty yellow guys growing on the roots of a removed redwood, and creepy slimy looking stuff on an old stump that will not die!!! It’s been a good year. The ones I eat are from the grocer.

    • One of our best memories ever is of warming a barstool in a beautiful little bar/restaurant in Mendocino when two women came in with a crate of Chanterelles (Cantharellus californicus). The chef appeared, paid cash for them on the spot, and after a bit all these magical side plates started to appear. This was during our carnivorous years so we capped the evening with a steak – covered in California chanterelles, butter, and garlic, harvested just hours earlier. It was enough to make us question our current vegetarianism.

      • Sounds delicious! I once had a chance to hike the forested hills of Idaho for wild mushrooms with a local guide. Fun and rewarding! Free stuff. Found stuff always tastes pretty good! Just don’t eat what you find in your front yard…go with a guide. They will tell you what’s safe, what’s not, and what’s not known.

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