Lethal Mushrooms Prompt Warnings From East Bay Park Officials

BAY AREA, CA – The Bay Area's recent bouts of rain brought welcome relief to our drought-plagued region, but it also encourages the growth of a looming menace: poisonous mushrooms.

The East Bay Regional Park District is warning residents to be extra vigilant when roaming the outdoors this fall, especially with dogs, as the poisonous mushroom season is upon us.

The region is home to two of the world's most deadly mushrooms, the aptly named Death Cap and Western Destroying Angel, according to park officials.

"Amanita phalloides (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. It fruits early in the fall, usually right after the first rains. It was accidentally introduced to North America on the roots of European cork oaks, and is now slowly colonizing the West Coast," according to Trent Pearce, naturalist with the Tilden Nature Area.

"Amanita ocreata (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," Pearce wrote on the park's web site. "It fruits from late winter into spring, and is associated exclusively with oaks. Unlike the Death Cap, it is a native California mushroom."

"Both of these species contain amatoxins, a group of molecules that inhibit cellular metabolism in many animals," the district said in a statement. "In mammals, the liver and kidneys are typically the fist organs
affected after ingestion."

"While these two species are responsible for most cases of mushroom poisonings in California, deadly amatoxins can be found in Galerina and Lepiota species as well, both of which occur in the Bay Area," Pearce said.

The district is reminding visitors that it's illegal to pick mushrooms or any plants found in the parks.

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--Bay City News contributed to this report/Photos of Amanita ocreata and Amanita phalloides by Trent Pearce, Naturalist, Tilden Nature Area via East Bay Regional Park District