Meeting report

Our group of 15 enthusiastic bryologists met in a layby at the perennially popular Blackrock Gate, in the upper Cheddar Gorge. We’d decided to spend the morning investigating bryophytes on the roadside walls and limestone exposures just downhill of our parking spot.

The walls were much admired and adorned with a characteristic suite of large Mendip mosses, including Plasteurhynchium striatulum, Neckera crispa and – demonstrating how sheltered the gorge is – in places, Hylocomiadelphus triquetrus. Best of all, we found a small population of Acaulon muticum where a bit of soil had developed on a wall-top. This species is unpredictable in occurrence in the area and is always an exciting find.

We then made our way onwards to some impressive cascading limestone rock outcrops on the warm side of the gorge (south- to east-facing). Although quite heavily disturbed by grazing ungulates, the slopes were full of bryophytes, including some of the anticipated Mendip specialities: Trichostomum brachydontium, Encalypta streptocarpa, E. vulgaris, Tortella tortuosa and T. nitida were all common. We also found lots of the rare Entosthodon pulchellus, distinguished from E. mouretii (up the road at Cheddar Head, but not seen here) by its asymmetrical capsule, Reboulia hemisphaerica, Scorpiurium circinatum, wispy-looking patches of Flexitrichum flexicaule and two rare Bryums – the large, cushion-forming B. canariense, which has a strong population in the gorge, and the more subtle B. kunzei, with its neat, bud-like shoots. Weissia controversa var. crispata, a scarce brownish plant, was also confirmed.

By now thoughts of lunch were encroaching, but an icy easterly was gusting down the gorge, so we retraced our steps to a more sheltered path taking us away from the road and slightly uphill. Another splendid (shady) wall just had to be admired before we had lunch out of the wind. Interesting species on the wall included some handsome patches of Mnium stellare, Seligeria pusilla, Taxiphyllum wissgrillii, Eucladium verticillatum and a lovely clump of fruiting Rhynchostegium murale.

After lunch we worked our way across some dull grassland above the Black Rock valley, eventually descending opposite the path from Velvet Bottom. It took a long time to descend this mainly south-facing slope, with its rich limestone grassland punctuated by low limestone outcrops because there was so much to see. Nearly all of the interesting species were on sparsely vegetated thin soil around the rocks. Here we found Tortella squarrosa, and some lovely, vividly coloured patches of Bryoerythrophyllum ferruginascens. Entodon concinnus was quite common and Archidium alternifolium, Cephaloziella divaricata and Fossombronia pusilla, which are all species suggestive of soil derived from glacial loess, were also seen. The highlight of this area, however, was a strong population of Bryum concinnatum, a species hitherto known only in N. Somerset from Velvet Bottom.

After that we had to investigate some interesting-looking north-facing rocks on the opposite side of the valley. Hylocomium splendens was abundant here and other interesting finds included Rhodobryum roseum and Hygrohypnum luridum. Pete and Rebecca found a small Lejeunea on rock and a tree branch, later confirmed as Lejeunea lamacerina.

Eventually, heading back along the Black Rock valley path, we could see how many recent changes there had been in this area. The prevalence of Ash die-back is high here and many of the trees on the valley sides had been taken down, sadly including ones that formerly supported Porella arboris-vitae. For an unknown reason, a section of drystone wall had also been reconstructed, resulting in, hopefully, only a temporary loss of the wonderful bryophyte populations it had supported. However, we were not very impressed by the amateurish attempts at reinstatement of the population, with handfuls of mixed loose pleurocarps simply being placed on top of the newly laid wall like a thatch!

Sharon Pilkington, 19 February 2025