WABbers were very quick to ID my last mystery fungus, and this one is probably just as easy...
I think it is an oyster mushroom,
Pleurotus ostreatus. It was a lone specimen spotted on a live beech in Holford Combe, Quantocks, in late September 2009.
Am I right? Any thoughts much appreciated!
On the same walk, I saw a beautiful pure white
Amanita type fungus, on the ground at the base of another beech. It looked a bit like my book's illustration of
A. vaginata, with a slender wavy stem and pronounced 'nipple' on top, but unlike that species had a very obvious ring and the cap was not heavily striated. I'm afraid I didn't photograph it.