This fungi was overwhelming a dieing beech tree on which this is a common host. Variable, overlapping slate blue,grey/brown fan shaped caps with an inrolled margin. White or pale straw gills radiate from the point of attachment where they may fork. Small lateral stem, downy when young.
Found on living, dieing and fallen logs od broadleaf trees. Rarely on coniferous trees. Late autumn through winter.
Increasingly cultivated for eating. They are firm and have a good flavour though the stem needs removing first.