Phellinus igniarius (syn. Phellinus trivialis), commonly known as the willow bracket, fire sponge, false tinder polypore, punk ash polypore, or false tinder conk, is a fungus of the family Hymenochaetaceae. Like other members of the genus of Phellinus, it lives by saprotrophic nutrition, in which the lignin and cellulose of a host tree is degraded and is a cause of white rot.

The fungus forms perennial fruiting bodies that rise as woody-hard, hoof or disc-shaped brackets from the bark of the infested living tree or dead log. The tree species is often willow but it may be commonly found on birch and alder and other broad leafed trees. The top is covered with a dark, often cracked crust, a stem is present only in its infancy. Unlike most fungi, it has a hard woody consistency and may persist for many years, building a new surface layer each year.

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