Community Corner

Deadly Mushrooms Growing In The East Bay

These mushrooms are one of the most toxic species on earth and they've popped up after our winter rains. They will kill people and pets.

EAST BAY AREA — They look a lot like the button mushrooms that you buy at the grocery store. Except these will cause severe gastrointestinal distress about 12 hours after you eat them, with liver and kidney failure following if you don't receive treatment right away. The name says it all: Death Cap. And they grow wild in the East Bay, along with a second mushroom called Western Destroying Angel.

Death Cap mushrooms typically pop up after the first fall rains. "Both the Death Cap and Western Destroying Angel grow near oak trees," said East Bay Regional Park District Naturalist Trent Pearce, who is based in Tilden Regional Park in Orinda and documents the fungi in East Bay Regional Parks. "They can be lethal to both humans and pets if consumed."

The Death Cap (Amanita phalloides) and Western Destroying Angel (Amanita ocreata) are two of the world’s most toxic mushrooms. 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, according to the parks district. Though 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.

Find out what's happening in Lamorindawith free, real-time updates from Patch.

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 disappears with age, and a thin white sac at the base. It is most common from late winter into spring. It is associated exclusively with oaks. Unlike the Death Cap, it is a native California mushroom.

"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."

Find out what's happening in Lamorindawith free, real-time updates from Patch.

Death Cap and Western Destroying Angel mushrooms are responsible for most cases of mushroom poisonings in California. However, two other mushroom species found in the Bay Area are also poisonous, the Galerina and Lepiota mushrooms.

While mushrooms and both beautiful and tasty, "Collecting mushrooms in East Bay Regional Parks is not allowed," said East Bay Regional Park District Public Information Supervisor Dave Mason. "The Park District urges the public to be safe and be knowledgeable about toxic mushrooms."

If you'd like to learn more, the East Bay Regional Parks will hold its annual Tilden Fungus Fair on Sunday, Feb. 3, 2019, at Tilden Nature Area’s Environmental Education Center.

(Get Patch real-time email alerts for the latest news from your California neighborhood. Also, download the free Patch iPhone app or free Patch Android app. Also, be sure to follow your local Patch on Facebook!)
Also See:


Get more local news delivered straight to your inbox. Sign up for free Patch newsletters and alerts.

We’ve removed the ability to reply as we work to make improvements. Learn more here