This is an extremely rare fungus. There have been 12 known sightings in Britain, but five of the
host trees are not thought to still exist. It is a Red Data List species.
It has been seen on english oak and holm oak. It is usually situated about 3 or 4 metres up the
stem.
Due to its rareity, little is known about the decay, but it is thought to cause a brown rot.
Phellinus robustus is a perennial, sometimes living for many years. One can count growth layers to
determine the age.