Growing on American Beech. I think this is the fungus associated with Beech Bark Disease: Neonectria faginata or Neonectria ditissima.
Could it be the waxy secretions of the insect itself? Cryptococcus fagisuga?
On concrete slab at parking lot for Samish Unit, Skagit Wildlife Area, which was formerly agricultural land. X. parietina appears to be rapidly increasing in Puget Lowlands, par