Xylobolus subpileatus

Xylobolus subpileatus is a species of crust fungus in the family Stereaceae first described in 1849 by Miles Joseph Berkeley and Moses Ashley Curtis. The fungus forms tough, crust-like fruit bodies with somewhat flat to wavy caps that feature a dark zonate top and light underside, typically growing on fallen oak logs. It creates a distinctive honeycomb-like decay pattern by selectively degrading lignin in the wood, with fruiting bodies appearing more frequently as the wood advances through decay. Though widely distributed across North America, Europe, Asia, and South America, X. subpileatus is considered endangered in several European countries, where it is often confined to old-growth oak forests....read more on Wikipedia.