Massed Colony of Lasiosphaeria ovinum
It is only recently that I became aware of this distinctive but tiny fungus species. It lives on dead wood, where I first found it in our garden. I have seen it in a few other localities but this impressive population was in our garden, and a wrist-thick Sycamore log, dead for at least four years.
If you want to see magnified images see:
Olympus EM-1, (aperture priority), Olympus 4/3 50mm f2 macro, f6.3 or f8, hand-held.
The stereos are crosseye.