Artist's Bracket

It is a wood-decay fungus, using primarily dead heartwood, but also as a pathogen on live sapwood, particularly on older trees. It is a common cause of decay and death of beech and poplar, and less often of several other tree genera. A peculiarity of this fungus lies in its ability to be as a drawing medium for artists. When the surface is rubbed or scratched with a sharp implement, it changes from light to dark brown, producing visible lines and shading.