Artist's conk

Ganoderma applanatum
A medium to large woody shelf-like mushroom attached to wood only along one side. The cap surface is dull and uneven, sometimes with concentric bands or furrows. The rather thick edge is turned under. The flesh is brownish and the white underside has tiny pores, often almost too small to be seen with the naked eye. The pore surface turns brown permanently after being injured, accounting for the name “Artist’s conk”, since detailed pictures can be scratched onto the surface and will persist indefinitely after the fungus dries.

Usually found on dead wood, but occasionally present on wounded live trees. Not edible.