East Bay Regional Park District officials are warning people to beware of the deadly mushrooms that crop up every rainy season.
Two of the world's most toxic mushrooms, the Western destroying angel and the death cap, both grow in the Bay Area and are common in the region's parks.
"Both of these toxic mushrooms can be lethal to humans and pets if consumed," said park district naturalist Trent Pearce. "They are mostly associated with oak trees and can be found growing anywhere oak roots are present."
The plants contain amatoxins that can damage the liver and kidneys in mammals.
Symptoms typically take up to 12 hours to appear after the mushrooms are consumed and start as severe gastrointestinal pain, progressing to the liver and renal failure if immediate treatment isn't provided, according to the park district.
The death cap is a medium or large mushroom that usually 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 was introduced to North America on the roots of European cork oak trees and is slowly colonizing the West Coast, park officials said.
The Western destroying angel is also a medium or large mushroom that has a creamy white cap, white gills, a white ring around the stem that fades as the plant grows and a thin white sac at the base.
It is a native California mushroom, according to the park district. Other toxic mushrooms that can be found in the Bay Area include the Galerina and Lepiota species.