Winter mushrooms can be deadly to humans and pets

Mushrooms that grow in the wild this time of year can look beautiful and are ecologically important, but some of them contain dangerous toxins.

The death cap (Amanita phalloides) and Western destroying angel (Amanita ocreata), two of the world’s most toxic mushrooms, can be found in local parklands during the rainy season.

They both contain amatoxins, a group of molecules that inhibit cellular metabolism in many animals and people.

Symptoms usually appear 12 hours after consumption, beginning as severe gastrointestinal distress and progressing to liver and renal failure if treatment is not sought immediately.

“Both of these toxic mushrooms can be lethal to humans and pets if consumed,” said East Bay Regional Park District naturalist Trent Pearce. “They are mostly 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. 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.

Other Bay Area mushrooms, including Galerina and Lepiota, may also carry deadly toxins, so it’s best to avoid anything growing wild.

“Collecting mushrooms in East Bay Regional Parks is not allowed,” noted public information supervisor Dave Mason.

To learn more, visit the Fungus Fair 10 a.m.-4:30 p.m. Jan. 25-26 at Tilden Nature Area’s Environmental Education Center, 600 Canon Dr., Berkeley.