Not having a copy of Paton is a pain when it comes to those liverworts that need checking microscopically. I collected this Lejeunea yesterday from acidic sandstone rocks alongside a wooded hillside stream above Treforest (ST09V), growing near R. aciculare and S. plumosum. Most leaves have only a few oil bodies but some towards the base of the shoot (first photo) have 10+, but I think it must be lamacerina or patens. The lobules are fairly big and the angle between lobule and main lobe looks quite acute, so I wondered if this might be patens?
Thanks as always for any help.