The East Bay Regional Park District issued an advisory Tuesday warning residents that two of the world’s most toxic mushroom species are now sprouting up around the Bay Area.
Amanita phalloides, or the Death Cap, and Amanita ocreata, or the Western Destroying Angel, typically grow in the Bay Area, but are particularly plentiful this year due to increased rain in the region, according to East Bay Regional Park District spokesperson Carolyn Jones. Jones said these mushrooms could be found in any park with trees in and around Berkeley, including Tilden Regional Park, Wildcat Canyon Regional Park, Robert Sibley Volcanic Regional Preserve, Huckleberry Botanic Regional Preserve and Claremont Canyon Regional Preserve.
The two species are responsible for most mushroom poisonings in California. Two other species of mushrooms found in the Bay Area — Galerina and Lepiota — are also poisonous. It is illegal for visitors to collect any kind of plant or fungi, including mushrooms, they find in an East Bay regional park.
Death Cap mushrooms are primarily found under oak trees, but are also found under other hardwood trees, whereas Western Destroying Angel mushrooms are associated solely with oak trees, according to the advisory. The only parks in the East Bay Regional Park District that are not potential homes to the mushrooms are shoreline parks where the soil consists mostly of sand, Jones said.
Death Cap mushrooms have a greenish-white cap, a white ring around their stem, white gills and a large white sac at their base. They are a medium-to-large mushroom, according to the advisory.
“Death Cap looks just like regular mushrooms,” Jones said. “You’d really have to be an expert to tell them apart from anything you’d buy at Safeway.”
Western Destroying Angel mushrooms are a medium-to-large mushroom with a “creamy white cap” and white gills, according to the advisory. They also have a thin white sac at their base and a white ring around their stem that disappears over time.
According to Jones, the mushrooms are only deadly if they are ingested. Both species contain amatoxins, which hinder cellular metabolism in many animals. In the alert, the East Bay Regional Park District warns park visitors to immediately contact a veterinarian if they believe their pet may have eaten one of the mushrooms.
Symptoms usually appear 12 or more hours after the mushrooms are consumed and begin as gastrointestinal problems. They could develop into liver and renal failure without immediate treatment.
“We’re not getting rid of them. They’re a natural, healthy part of a normal forest,” Jones said. “Just leave them alone. Don’t eat them, don’t let your dog eat them, don’t kick them over.”