Nant-y-Ffyllon is a small, tumbling, fast-flowing stream in a rather open, partially wooded valley.
There was a healthy population of what I'm fairly convinced must be Platyhypnidium lusitanicum, which I came across today during a smash and grab raid into SS89L in an attempt to take it over the 60 mark. Unfortunately, although it looked different, I wasn't really sure what it was when I saw it and because it was all under water, rather annoyingly I never photographed it in situ. Hopefully, the images below will give Sam the opportunity to confirm (or otherwise) and if correct I'll package my sample of this potential county first. Plants formed quite robust, mono-specific, trailing masses of long stringy shoots on under water rocks, patches being regular along the 50m section I walked. Indirect associates, in decreasing levels of abundance, included Hyocomium armoricum, Racomitrium aciculare, Scapania undulata, Sciuro-hypnum plumosum, Pellia epiphylla, Sphagnum denticulatum and Dichodontium palustre.
The only other species of note was Lophocolea bispinosa, a small patch gaining a toe-hold on a soggy section of forest track.