A large thick perennial bracket usually found on willow trees, sometimes hoof-shaped.  Upper surface is hard and woody, with concentric ridges, and is grey or black, with a paler reddish margin.  Older specimens are cracked and blackened as though they have been in a fire.  The under surface has fine pores at 4 - 6 per mm. and is reddish or grey.  

There are several other Phellinus species, and P igniarius may be a species complex requiring DNA analysis to separate. Other polypores and brackets can be similar; the hoof fungus Fomes fomentarius is usually on Birch trees.

Photograph upper and lower fertile surface to show pores; you must note host plant and substrate

Usually living willow trees, but also other broadleaves including alder, birch and apple