Since then the site has been on my 'to do' list, and a sunny 27th April seemed ideal. I didn't find B. stricta or any more of either Grimmia, but there were several other good species present, including Marchesinia mackaii (photo), Bartramia ithyphylla, Pohlia cruda, Frullania fragilifolia, Seligeria recurvata, Plagiochila bifaria, P punctata & P spinulosa, Porella arboris-vitae (photo) and Orthothecium intricatum.
The two rarest species were the Nationally Scarce Plagiopus oederianus (photo, with some Bartramia pomiformis for comparison), which is abundant on north-facing rock outcrops, and the Nationally Scarce Encalypta ciliata (photo), which was only present in one small area and was last recorded on the site in 1923.
Biggest surprise was a tuft of Orthotrichum rupestre (photo), which only has 3 previous Radnorshire records and remains unknown further SW in Wales. Its very hairy calyptra, superficial stomata, upright exostome teeth and half-pliccate capsules were distinctive.
I thought that the highlight of the day was going to be a round-leaved liverwort in a flush, which clearly wasn't Odontoschisma and seemed sure to be my first ever Jamesoniella undulifolia. To my shock and disappointment, I found under the microscope that it had violet rhizoids, making it Jungermannia hyalina very out of habitat.
Overall it was a wonderful day of mossing, and the site is clearly of SSSI quality for its bryophytes.