Crust Fungus

An unidentified white crust fungus growing on a small dead oak tree (Quercus sp).  It had a texture  rather like cream cheese.

I took this specimen:

This yielded the following spores (magnification x600, field width 86um):

These are about 5.5 x 5um.

The basidia have 3 sterigmata (x600, width 86um):

And the hyphae have clamp connections(x600,  width 86um):

First photo and specimen taken in the Wilderness, Whiteknights Park, Reading, UK, on 2014-01-11.