Brown Crust Fungus

A brown crust fungus, probably Hypoxylon petriniae, growing on a branch fallen from an ash tree (Fraxinus excelsior).

I took this specimen home with me:

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

These are about 10 x 4.5um which is just a little thinner than the 8.8-11.5(-13) x 4.8-6um given for Hypoxylon petriniae given here.

First photo and specimen taken in Whiteknights Park, Reading, UK, on 2014-02-09.