Another toothed crust fungus, this time probably Radulomyces molaris (= Basidioradula molare), again probably on a fallen oak branch.
I took this specimen:
And the specimen yielded these spores (magnification x600, field width 86um):
These spores are about 9 x 6um which is distinctly fatter than those of Basidioradulum radula found here, and which agrees well with the ranges of about 8-12 x 6-8um often quoted for R. molaris.
First photo and specimen taken in Whiteknights Park, Reading, UK, on 2013-12-24.