The photo shows some Stag's-horn Clubmoss (Lycopodium clavatum) which was found today on a north-facing, mossy bank growing among heather, near Resolfen.
This is a very uncommon plant in Glamorgan and records of it in the county since the 1970s are few and far between. The Resolfen population is quite large (about 10 square metres) and the habitat it occurs in may have survived here for many decades, narrowly missing destruction by the development of conifer plantation. Amazingly, there were also scattered plants of Fir Clubmoss (Huperzia selago) growing along side it and nearby there was a small population of Round-leaved Wintergreen (Pyrola rotundifolia).
Clubmosses are vascular plants, related to ferns and usually associated with montane habitats. They are not mosses. The occurrence of this relict community in the middle of the Neath Valley gives us a fascinating glimpse of what must have been a more widespread feature of local vegetation once upon a time.