OAKLAND, Calif. (KRON) — Two of the world’s most toxic wild mushrooms, named “death cap” and “destroying angel,” are beginning to fruit and spread in the East Bay, park officials warned Thursday.

These mushrooms contain amatoxins, molecules that are deadly if consumed.

The death cap (Amanita phalloides) and Western destroying angel (Amanita ocreata) grow every winter when the weather turns wet and rainy.

“This year’s heavy rains have created a mushroom bonanza in the East Bay Regional Parks. The Park District urges the public to be safe and knowledgeable about toxic mushrooms,” park officials wrote.

EBRPD naturalist Trent Pearce said, “Both of these mushrooms are mainly associated with oak trees and can be found growing anywhere oak roots are present. They can also be lethal to humans and pets if consumed,” Pearce warned.

Symptoms may not appear until up to 12 hours after consumption, beginning as severe gastrointestinal distress. Symptoms progress to liver and kidney failure if treatment is not sought immediately, parks officials said.

“The best way to stay safe is to learn to recognize our poisonous mushroom species,” Pearce said.

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 death cap is not native to California. It was accidentally introduced to North America on the roots of European cork oaks and is now slowly colonizing the West Coast.

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 can disappear with age, and a thin white sac at the base. It is also associated with oak trees.

Unlike the death cap, the destroying angel is a native California mushroom.

“Collecting mushrooms in East Bay Regional Parks is prohibited, but we encourage people to take photos of them and enjoy them like you would wildflowers or birds,” Pearce said.

Fungi are an ecologically important part of nature.

While the death cap and western destroying angel mushrooms are responsible for most cases of mushroom poisonings in California, deadly toxins can also be found in Galerina and Lepiota mushroom species, which also grow around the Bay Area.