Pleurotus ostreatus
Veronica, I think this could be an oyster mushroom. They are common on deadwood of deciduous trees, I find them usually on dead beech stems.
I linked my spotting below.
http://www.projectnoah.org/spottings/764...
Lat: 52.35, Long: 4.62
Spotted on Oct 15, 2006
Submitted on Oct 17, 2011