Bitter Bolete

Photo of broken bolete mushroom cap, being held to show pores
Safety Concerns
Not recommended/not edible
Scientific Name
Tylopilus felleus

Large, tannish brown cap with pinkish white pores; webbed, tannish brown stalk. Grows singly or scattered on the ground in mixed woods. June–November. Cap convex, becoming flat; tannish brown to buff; texture sticky when wet; flesh is thick, white. Pores small; round; pinkish white, turning pale pink with age. Stalk thick, enlarging toward the base; tannish brown, sometimes bruising brownish, with brown webbing; webbing, sometimes raised. Spore print burgundy brown. Spores magnified are smooth, elliptical.

Lookalikes: Other boletes, some of which may be edible.


Cap width: 2–6 inches; stalk length: 1½–4 inches; stalk width: ¼–1¼ inches.

Where To Find
image of Bitter Bolete Distribution Map


Grows singly or scattered on the ground in mixed woods.

Not edible. If you are tempted to taste, beware! The bitter bolete can be extremely bitter. This species resembles the choice king bolete (Boletus edulis), which does not grow in Missouri but can sometimes be found in stores.

Life Cycle

This species is mycorrhizal: It exists most of the time as a network of cells (mycelium) connected to tree roots, in a symbiotic relationship with the tree. (Many trees fare poorly without their fungal partners.) When ready to reproduce, the mycelium forms the mushroom aboveground — this is the reproductive structure. In boletes, spores are produced in the pores under the cap and are released to begin new mycelia elsewhere. The mycelium of a mushroom can live for decades.

It is easy to get caught up in hunting mushrooms for eating. But keep in mind that inedible fungi have important roles in nature, and that they possess a beauty in color and form that humans can enjoy.

This is one of many fungus species that help nourish forest trees through symbiosis. The netlike fibers of the fungus cover the surface of a tree’s roots, increasing the surface area and the roots’ ability to absorb water and nutrients. In return, the tree shares nutrients with the fungus.

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Similar Species
About Mushrooms in Missouri

Mushrooms are a lot like plants, but they lack chlorophyll and have to take nutrients from other materials. Mushrooms are neither plants nor animals. They are in a different kingdom — the fungi. Fungi include the familiar mushroom-forming species, plus the yeasts, molds, smuts, and rusts.

Always be cautious when eating edible mushrooms. Be absolutely sure of the ID, and only eat a small amount the first time you try it to avoid a reaction..