I've been looking back at some bryophyte samples I collected last summer at a location on the western edge of Dartmoor. The geology was Devonian slates and siltstones and the collections were made in an apparently permanently damp rocky area near a stream.
I'm fairly certain this is the leafy liverwort Plagiochila porelloides. Leafy liverworts are not really my thing, and in the past I've found them quite hard work to identify. However, the BBS Field Guide does make things a bit easier. At first I thought I had P. asplenoides, but the presence of thread-like side shoots near the base is characteristic of P. porelloides, and not seen in P. asplenoides.
Shoot tip x10
Here is another leafy liverwort, Jubula hutchinsiae (x20) collected from the same location