Spring meeting 1984: Brecon

HomeEventsSpring meeting 1984: Brecon

12 April 1984 - 17 April 1984

Meeting report

From the initial get-together in the bar at the Castle, this promised to be a memorable meeting and the enthusiasm both of the members and the weather subsequently made this a reality. All sites visited were in v.-c. 42.

The chosen sites all lay within the Brecon Beacons National Park and it was thought to be appropriate that on the Thursday morning, 12 April, an introduction to the area’s geography and geology should be given at the mountain centre at Libanus. In the event, the member of the NP staff who was to have given the talk was not available and Ray Woods, our local member and assistant Regional Officer for the Nature Conservancy Council in Breconshire, gave a brief introduction to the week’s programme.

A short distance away was the first site, Traeth Mawr, a small raised mire with peripheral wet flushes, managed as a reserve by the Brecknockshire Naturalists’ Trust. Here Scorpidium scorpioides was much in evidence in the peaty flushes along with Drepanocladus revolvens, *D. exannulatus var. exannulatus and Plagiomnium elatum. The raised mire supports seven common species of Sphagnum growing amongst which was noted Odontoschisma sphagni and Mylia anomala, now scarce species in mid-Wales due to the general decrepitude of peatlands. Find of the week was possibly Joan Appleyard’s *Dicranum leioneuron previously only known in Wales from raised mires in Cardiganshire. Lunch was a rewarding experience for some of us, taken on a roadside verge surrounded by Hypnum lindbergii and Archidium alternifolium.

After lunch, a move was made to the River Usk, a few miles east of Sennybridge, where we were joined by a number of members from the Reading area and the afternoon was spent searching the river-banks and boulders, the latter well exposed due to the low water level. Orthotrichum rivulare was abundant on riverside trees, from where Tortula subulata var. subinermis was also recorded. An old record for Epipterygium tozeri was confirmed and Ulota phyllantha, a scarce species in mid-Wales, was also seen.

13 April. The River Nêdd at Pont-melin-fach below Ystradfellte was the venue. This wooded valley is owned by the Forestry Commission but the area near the river is relatively undeveloped. Downstream from the bridge the rock is Millstone grit with a characteristic ‘acid’ bryophyte flora, and luxurious patches of Jamesoniella autumnalis and Dicranum fuscescens were not uncommon on the trees and rocks. On a stump was found Dicranum flagellare, a second county record, and other notable species included Dicranodontium denudatum and fruiting Diphyscium foliosum. Lunch was delayed to allow a visit to be made to a most impressive waterfall a few hundred yards further downstream.

Upstream, in complete contrast, the rocks were flushed with lime-rich water and prolific growths of Neckera crispa hung in curtains from the outcrop, providing a very different impression of a plant familiar to those living near the chalk grassland of the south-east. Eucladium verticillatum andCratoneuron commutatum var. commutatum had reacted with the water to produce large deposits of tufa, forming a substrate for Cololejeunea calcarea. The high relative humidity and possible absence of recent disturbance was reflected in the presence of Bazzania trilobata and both Wilson’s and Tunbridge filmy ferns.

14 April. Saturday found the party, now 28 in number, at Craig-y-Rhiwarth in the River Tawe valley near Craig-y-nos Country Park. The initial climb up the hill from the carpark was through dry limestone woodland. Nowellia curvifolia was seen in an uncharacteristically exposed position whilst logs elsewhere in this wood proved fruitful with Dicranodontium denudatum, Tritomaria exsectiformis and Lophozia incisa recorded, the latter two by Jean Paton.

Lunch was enjoyed in brilliant sunshine, sheltered by the ridge from a cutting east wind. A descent through a natural rock arch resulted in the rediscovery of the near century old record Tortella nitida made by the Rev. A. Ley. On shaded, wooded cliffs Seligeria acutifolia was noted, here in a new locality remote from all its previously known Brecknock sites. Other species of note seen during the day included Scapania aspera, Riccia warnstorfii and Orthothecium intricatum.

Time allowed a short visit to the National Trust-owned Henrhyd Waterfall; the gorge of the Nant Llech here cut into coal measure shales and sandstones. Intrepid members examined the rocks behind the falls and in the gorge below. The abundance of Leiocolea bantriensis and Blepharostoma trichophyllum was notable, together with Tetrodontium brownianum on damp shaded rocks. Fissidens celticus was observed on a steep bank by the path.

15 April. On Sunday the banks of the River Usk were again visited, at Llangynidr Bridge, where the character of the river is quite different and large sandstone boulders are a feature. A search above and below the bridge produced Schistidium alpicola var. alpicola, Bryum gemmiparum (a national rarity not seen in the county since 1914), Pohlia lutescens, Epipterygium tozeri, Fissidens crassipes (second county record), F. rufulus, Barbula trifaria and B. spadicea. On tree bases Orthotrichum sprucei, O. rivulare and Scleropodium cespitans were frequent.

In the afternoon, the nearby Tal-y-bont reservoir was the centre of attention but the banks proved unrewarding and the party split up to examine the head water streams and cliffs of Craig-y-fan Ddu. Richard Fisk’s discovery of Splachnum sphaericum on sheep dung, apparently not previously noted from the Beacons, was the only notable find.

16 April. Monday saw a return to the limestone, to the cliffs and quarries of Dyffryn Crawnon. Hail showers pursued the party up the valley, where part of the steep, predominantly ash, woodland is a Naturalists’ Trust reserve. The quarries above, which had been worked in the recent past for limestone, proved disappointing owing to the extreme dryness; however, the line of the tramway above and below less disturbed cliffs was followed round the head of the valley until the transition to the Old Red Sandstone was indicated by the abundance of fruiting Bartramia pomiformis. Species of note on the limestone included Seligeria pusilla, S. acutifolia and Encalypta vulgaris. The party split, those returning to the valley floor noting beneath a limestone face, Orthothecium intricatum and Plagiopus oederi. A more wide-ranging group recorded Lophozia excisaRiccardia palmata, R. sinuata, Cephaloziella hampeana and Mnium marginatum. Marcus Yeo collected a Scapania which Jean Paton confirmed to be *S. lingulata, new to Wales. The ash woodland provided few notable epiphytes, Pterogonium gracile being the exception.

P. J. Port & R. G. Woods

17 April. Although the wind had changed to the South for the last day, it was still cool and became cloudy, after a clear start. The approach to the Pen-Moel-Allt woodlands involved a circuitous and somewhat alarming convoy through the back streets of Merthyr. The clay-and-gravel track had Archidium alternifolium, and soon limestone appeared in the banks and walls with large cushions of Ctenidium molluscum, Barbula recurvirostra, well-grown Neckera crispa, and other species for the recording card. Soon, our party – of thirteen – cut down through very dense Larch to the north end of the Pen-Moel-Allt cliffs, a north-east facing scarp of Carboniferous limestone overlooking the Afon Taf Fawr. The scarp consists of a series of low limestone cliffs above steep – and rather slippery – slopes of clay and scree, with open Ash, Wych Elm, Oak and Hawthorn on and between the outcrops. To southward the slope steepens, and a tall cliff at some 300m altitude forms the major outcrop. In the many dry and damp habitats present bryophytes were abundant, with such species as Scapania aspera, Thamnobryum alopecurum, Plagiochila britannica and fruiting Ctenidium molluscum. Small species of the bare rock were Seligeria acutifolia, Cololejeunea calcarea and Tortula intermedia. In cracks and on soil-covered ledges was a rather confusing form of Trichostomum brachydontium. In general the cliffs were dry, and in only a few places was water-seepage evident, with Orthothecium intricatum and Jungermannia atrovirens. On trees were good growths of Lejeunea cavifolia, an d one alert member spotted two patches of Ptilidium pulcherrimum on an oak-trunk. Besides the 105 species of bryophytes we saw fine colonies of all three Polypodium ferns, and Mr Nethercott pointed out Sorbus leyana, a Whitebeam microspecies completely restricted to this valley, and the local S. rupicola.

Later in the afternoon on the return to Brecon we stopped at a gully on Craig Y Fro, a frowning rough cliff by the road just north of the pass. The time available, however, proved totally inadequate, and we retreated with fine fruiting Isopterygium pulchellum as perhaps the best find. The richness of this area was in fact revealed by a “splinter-group” of three members, who spent the whole day on the nearby – and much more extensive – Craig Cerrig-gleisiad, recording 150 species. Among many good finds were Eremonotus myriocarpus, Anoectangium aestivum (c.spor.), Grimmia torquata, and Isopterygium pulchellum.

In the evening eleven remaining members were made welcome at a restaurant in Brecon. We had a room to ourselves, and a most pleasant meal, amongst other things memorable for the sight of certain ladies of the group in evening attire, and for the production, from somewhere, by one of these ladies, of a pocket-lens to identify an ambiguous object in someone’s sweet-course. The meal proved a very satisfactory way to round off the week: we toasted the health of the hard workers who had arranged for us such a varied and successful week – especial thanks to John Port, local secretary, and Ray Woods, NCC representative, who chose the sites so well.

F. J. Roberts