What am I ?

What am I ?

Observation - What am I ?. Description: This rather large fungus seen growing at the base of a decaying beech tree. It's approximately 40cm x 40cm. I'm really struggling to identify it and welcome any suggestions...

This rather large fungus seen growing at the base of a decaying beech tree. It's approximately 40cm x 40cm. I'm really struggling to identify it and welcome any suggestions...