Leucobryum in Crynant (photo taken in July 2014)
L. glaucum is more likely in this sort of habitat than L. juniperoideum (I thought). I remember checking the leaves and convincing myself that the lower, wide portion was at least as long as the narrow upper part. I recorded L. glaucum. When I revisited my specimens today I found leaves that would fit descriptions of either or both species (re: Barry's comments in last post), some with very long narrow upper portions that I shouldn't have ignored at the time. So, I cut some leaf costa sections from the lower part of the leaf and they show the 2-cell thick structure that is indicative of L. juniperoideum.
Now, when I look at my original photos the colonies do look more lax than the typical compact cushions formed by L. glaucum, of which there are classic examples in the lower Hepste valley below Scwd yr Eira. Mea culpa.