I visited Craig y Castell and part Craig y Cilau near Llangattock last week – I didn’t intend to look at bryophytes, but it is difficult to switch off completely at such a rich site.
With the bracken now died back and partly broken up by grazing animals, I was surprised just how many scattered rocks/boulders are present in some areas, with all but the largest tending to be completely hidden by the bracken in summer.
Most of the big blocks are limestone with a lot of the smaller ones acidic grits and sandstones. As I wandered around I noticed each acid rock seemed to have a slightly different bryophyte flora to its neighbours. One of the largest had a nice colony of the lichen Sphaerophorus globosus, whilst others had big patches of things like Racomitrium lanuginosum, Lophozia ventricosa, Tritomaria quinquedentata, Barbilophozia attenuata and Campylopus fragilis was present on a few. About half a dozen rocks also supported colonies of Tritomaria exsectiformis /exsecta (reddish-brown and green patches in the photo).
A few years ago Sam and I recorded T. exsecta from nearby woodland, so I checked one of these colonies and sure enough the rounded gemma showed this too to be exsecta.
Perhaps all the colonies I spotted were exsecta?.
The limestone blocks and more lime-rich sandstone blocks also have some interesting things, mostly lichens, but there are often large patches of Neckera crispa and Scapania aspera and I also spotted things like Leucodon sciuroides (probably new to the site), fruiting Tortella tortuosa, a form of tortuosa with very fragile leaves and a large block sported five tufts of fruiting Entosthodon muhlenbergii.
Away from the boulders and bracken other things of interest, included a sheep’s skull with a small tuft of Orthotrichum pulchellum, some broken branches of a hawthorn below Craig y Castell had what I presume is Agyrium rufum,
which has been recorded from the nearby NNR in the past. Ledges in a quarried area had a few tufts of Encalypta vulgaris and a dark scum on a damp quarry face on closer inspection was found to be Seligeria patula (presumed). A few patches of the scarce lichen Solorina spongiosa
were also growing on an eroding bank by a path. Now that days are getting longer, some vascular plants were starting to show, with endemic hawkweeds beginning to put out new leaves, rue-leaved saxifrage flowering and I also spotted a single plant of Hutchinsiaand some sort of cabbage has found its way onto the cliffs
In future I will pay more attention to boulders that are hidden by bracken in summer.