What Are Bright Yellow Mushrooms or Toadstools Growing Around the Base of Oak Stumps?

Chicken of the Woods

• Also called hen of the woods or sulphur shelf, this large, fleshy mushroom is native to hardwood forests in Eastern North America. It causes heart rot in standing and fallen oaks. A related fungus, Laetiporus cincinnatus, primarily attacks the tree's butt. Several similar species also grow in Western North America. These fungi form fan-shaped growths, sometimes singly and sometimes layered, producing a fleshy comb. Chicken of the woods grows up to 2 feet across and has a bright yellow-to-orange surface when young, eventually fading to white or pale yellow. This mushroom is edible and is often used in casseroles.

Golden Chanterelle

• The golden chanterelle is a type of edible mushroom native to the western half of North America, particularly along the coast. Some subspecies, such as the California golden chanterelle, prefer oak trees and can grow to enormous size. These yellow-to-pinkish mushrooms are prized for their large size and distinctive taste. They produce large, fan-shaped fruiting bodies at the base of oak trees in fall and winter. Often muddy, wash these mushrooms before eating, but they are safe for most people.

Jack O' Lantern

• Jack O'Lantern fungi superficially resemble young golden chanterelle mushrooms with bright yellow-to-orange caps and a fan-shaped growth habit. These mushrooms grow on clusters on or near wood, including oak stumps. Unlike many poisonous mushroom, Jack O'Lanterns don't taste or smell bad. However, they can cause serious digestive problems, including vomiting, cramps and diarrhea.

Fly Agaric

• Most fly agaric mushrooms are bright red or orange, with white speckles. However, Amanita muscaria var. formosa and Amanita muscaria var. guessowii have dull- to bright-yellow caps instead. This classic toadstool grows throughout North America and can reach dinner plate sizes. Fly agarics grow around both conifers and hardwoods, including oak trees. These mushrooms are toxic and can cause hallucinations, nausea, twitching, agitation, confusion and irritability. In serious cases, victims may suffer from seizures or coma, but most people recover within a few days.