Cwm Marydd - the best of Brechfa

Less than 10 minutes' drive from Cwnc y Llwyn is the steep-sided valley of Cwm Marydd (SN5031).  It doesn't look like much on OS maps or aerial photos, but very steep sides, rock outcrops, a series of cascades, relatively old Oak & Ash, and even a mine adit (not marked on any map I've seen) make it a perfect site for bryophytes.  The bryophyte species list stands at 120, and includes Tritomaria exsecta at its only recorded site in VC44, Cephalozia catenulata, Plagiochila exigua, P. punctata, P. spinulosa, Jubula hutchinsiae and Platyhypnidium alopecuroides.  I have visited on 6 occasions before, and spent an hour there this afternoon to stretch my legs during Half Term.

Highlight was locating two trees with Plagiochila exigua alongside a waterfall at SN50383202 and SN50363199: finally getting GPS readings for this, the only known population in Brechfa Forest.  Alongside both were patches of a toothier Plagiochila with scarcely decurrent leaves that I assume is P. punctata, although its non-deciduous leaves and brown colour make me a little suspicious and I need to investigate further [I did and it still looked odd, but I'm certain it's P. punctata, with the non-papillose cuticle ruling out the far-fetched Macaronesian P. stricta].  A lot of staring at Lejeuneaceae failed to reveal anything notable, which was a surprise.

Plagiochila exigua

Interesting Plagiochila punctata with slightly decurrent leaf bases, a brown colouration like P. bifaria, and non-deciduous leaves

Two nice lichens were also present: the pink-fruited Mycobilimbia pilularis (spores checked today) was on an old Ash alongside P. exigua, and the tiny Graphina pauciloculata grew with G. ruiziana on a Hazel (microscope checking needed).  Three patches of a large lichen in the canopy of the Ash need a revisit with a telescope...

Jamesoniella and Plagiochila in abundance

Graham and I searched another previously unknown section of Coedydd Nedd a Mellte SAC today, with oceanic liverworts our primary focus.  This went pretty well, overall, despite stygian darkness that made the search difficult.  Some sections of the Nedd are outstandingly rocky and bryophyte-rich!

We parked at Pont Melin-fach and started off on the west bank downstream of the carpark.  This area (SN90611025) holds one of the largest populations of Jamesoniella autumnalis either of us had ever seen, with some Oak trunks supporting 10s of extensive patches.

The entire bryophyte cover on this tree trunk is Jamesoniella!

After GPSing a good number of Jamesoniella trees and noting Tritomaria exsectiformis and Anastrophyllum hellerianum, we returned to the carpark and headed upstream, again on the west bank.  Jamesoniella and Anastrophyllum were each encountered a few times upstream of Pont Melin-fach, but never in abundance.  Instead, Plagiochila punctata was remarkably abundant, with Graham locating at least 4 colonies including one tree at SN90881076 with 50+ patches of this liverwort.  Although there are a few scattered colonies of P. punctata in the SAC, it is much rarer here than P. spinulosa.  Plagiochila bifaria was also present on one tree, and P. spinulosa was on a few rocky areas.

Remarkably, the Plagiochila punctata trees were in clifftop woodland; Graham is looking at the main tree.

Just before we reached the Plagiochila hotspot, I spotted 6 patches of Drepanolejeunea hamatifolia on a relatively young Ash by a cascading sidestream (SN90871068).  This is about 1.5km from the only previous record of Drepanolejeunea from the SAC, found a couple of months ago.

Further upstream, we found an area of rocky woodland where Bazzania trilobata was locally abundant, with 20+ patches in a 10x10m area (SN91001088).  Despite Coedydd Nedd a Mellte supporting the best example of Oceanic woodland in south Wales, there are very few colonies of Bazzania on the site, even though this species is found much further south and east in Wales than the SAC's rarer oceanic liverworts.

The final notable liverwort of the day is, like Bazzania, more interesting in a Coedydd Nedd a Mellte context than in a wider south Wales context: we found Colura calyptrifolia on at least 4 Hazel and Ash around SN91121105.  Despite this species being found in most of south Wales' conifer plantations, often in great abundance, this is only the 2nd or 3rd time is has been seen in the SAC.  It is, of course, a Hyperoceanic liverwort that used to be restricted in Wales to a few of the best oceanic woodland ravines, and its rarity in south Wales' ravines (even where Aphanolejeunea, Drepanolejeunea, Harpalejeunea and Plagiochila exigua are present) is intriguing.

Another section of this amazing site has now been explored, and more bryophyte hotspots found.  There's still the area upstream of Pont Rhyd-y-cnau to be done, plus the central Mellte.

Forestry etc in NE Carms

I spent a couple of hours in SN73D, which includes the village of Porthyrhyd, on 17th October.  The tetrad already had 75 species recorded, mostly by Jonathan Graham, but I am trying to visit all Carms tetrads myself and this one looked pretty diverse.  My visit revealed 129 species, most of them in the Banc-y-garreg Forestry, and took the tetrad total to 147 (Jon had several additional species including Bazzania trilobata from the inaccessible private rocks on Banc Bwlchdrebannau).

The forestry tracks were notably species-rich, with highlights including Archidium, Fossombronia wondraczekii, Riccia glauca, 1 fruiting rosette of Phaeoceros laevis, Campylopus subulatus, Bryoerythrophyllum ferruginascens, Pohlia drummondii and female Jungermannia hyalina.  In contrast, epiphytes were rather limited and I failed to find any Colura (!) although most of the other willow regulars were present.  As I continued deeper into the forestry I found a clearfell area with 3 or 4 very small rock outcrops (each <5x2m in extent), and to my surprise these held Barbilophozia attenuata, Plagiochila punctata, P. spinulosa and Sphagnum quinquefarium.  Riccardia palmata on damp conifer logs was new for the hectad.

The trackside habitat of Jungermannia hyalina and the Plagiochila punctata outcrop (iPod photos) 

This productive first hour was followed by a fairly fruitless session along the lanes approaching Olchfa Mill, with Ctenidium, Pellia endiviifolia and a few species by a rocky stream being the only additions.  The tracks along Banc Bwlchdrebannau were even worse, as all the good rocky habitat is set well back on private land.  Luckily, things ended on a good note with a visit to Porthyrhyd Chapel, which held a good range of typical churchyard mosses including Encalypta streptocarpa, Pseudocrossidium revolutum, Gyroweisia tenuis, Schistidium apocarpum and Ephemerum minutissimum.

 

There are still >80 tetrads I haven't visited, most of which are light blue on this coverage map