Vice-county 44 (Carmarthenshire)

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Bannau Sir Gaer (the Carmarthen Fans) is one of the bryophyte hotspots of south Wales, with species such as Scapania gymnostomophila on base-rich sandstone outcrops

The following account has been taken from The Mosses and Liverworts of Carmarthenshire (2006) with updated names and a few additional sites and species.

Sam Bosanquet, December 2020

Broad bryophyte habitats

Broadleaved woodland

A significant part of Carmarthenshire’s land is wooded, probably because most river valleys are steep-sided and narrow.  Oak woods predominate, most of them composed of sessile oak rather than the pedunculate oak, but ash is also widespread and dominates in some woods on the limestone ridge, sycamore forms some coastal woodlands, and willow, alder and birch form carr on wetter ground.  There are also numerous patches of scrub scattered through the county’s agricultural land, in former industrial areas and on the coast.

Lowland woodland often has a ground layer dominated by vascular plants but steeper banks hold large mosses, including Atrichum undulatum, Brachythecium rutabulum, Eurhynchium E. striatum, Kindbergia praelonga, Mnium hornum, Plagiomnium undulatum, Polytrichastrum formosum and Thuidium tamariscinum.  Tree bases are clothed in pleurocarpous species, such as B. rutabulum and Isothecium myosuroides, with Hypnum andoi and patches of Frullania dilatata, Metzgeria furcata and Orthotrichum spp. further up the trunk.  An understorey of blackthorn, elder and hazel increases the epiphyte diversity, supporting Metzgeria violacea, Neckera pumila, Orthotrichum pulchellum and O. tenellumCalypogeia fissa, Dicranella heteromalla and Pseudotaxiphyllum elegans become prominent on the floor in acidic woodlands, whilst Thamnobryum alopecurum is locally abundant in calcicolous woods on the limestone ridge.  Rotting logs in lowland woods are usually colonised by Lophocolea bidentata, L. heterophylla, Eurhynchium praelongum and, sometimes, Tetraphis pellucida.

Sessile oak woods predominate in the western hill country and north-eastern uplands as well as steep-sided valleys elsewhere.  Bilberry is the principal vascular plant on the floor and mosses are often abundant among its bushes.  Typical species include Dicranum scoparium, Eurhynchium praelongum, Hypnum jutlandicum, Mnium hornum, Plagiothecium undulatum, Polytrichtrum formosum and Rhytidiadelphus loreus, with Dicranum majus on steeper banks.  In the most humid parts of the north-east, such as Gwenffrwd RSPB and Nant-y-clun, the liverworts Bazzania trilobata and Plagiochila spinulosa and the moss Sphagnum quinquefarium become very locally abundant.  Other liverworts, including Calypogeia fissa, Lepidozia pearsonii, L. reptans, Saccogyna viticulosa and Tritomaria quinquedentata, grow through or over these bulky species.  Tree boles are usually covered with Isothecium myosuroides and trunks with Hypnum andoi, but epiphytes can be diverse where humidity levels are high.  Frullania tamarisci, L. reptans, Plagiochila spinulosa, Scapania gracilis and Dicranum scoparium are all locally abundant on oak trunks, with Orthocaulis attenuatus and P. punctata occasionally encountered.  Hazels and willows in the uplands support a different range of epiphytes, with Metzgeria furcata, M. consanguinea, Microlejeunea ulicina and Ulota crispa sl typical.  Cephalozia curvifolia is the principal colonist of decorticated logs in these humid woodlands, often turning them red.  Lepidozia reptans, Lophocolea bidentata are also common on logs in the uplands, whilst several scarce species, including Anastrophyllum hellerianum, Cephalozia lunulifolia, Odontoschisma denudatum and Tritomaria exsectiformis are surprisingly regular around Mynydd Mallaen.

A log in woodland near Mynydd Mallaen supporting Bazzania trilobata and other liverworts

Many valleys in Carmarthenshire hold wet woodland, dominated by alder, birch or willow.  Chiloscyphus pallescens, Pellia spp., Brachythecium rivulare, B. rutabulum, Calliergonella cuspidata and Eurhynchium hians are regular on the floor in these woods, sometimes to be joined by Calliergon cordifolium or Oxyrrhyncium speciosum.  Flushes in riparian woodland tend to be dominated by B. rivulare, sometimes with abundant Trichocolea tomentella or Hookeria lucensLeptodictyum riparium is locally abundant on the ground in wet woodland next to the Afon Tywi.  Sphagnum spp. may carpet the floor of the birch carr that develops around bogs and poor fens and in valley bottoms in the uplands; the remarkable Aneura mirabilis is a denizen of this uncommon habitat.  Willow carr is usually rich in epiphytes, with up to seven species of Orthotrichum present in some stands; alder and birch tend, in carr, to support rather few epiphytes.

Parkland and wood pasture, considered conservation priorities for their lichens and invertebrates, tend to be bryologically unremarkable.  A few mature trees, especially ash, support interesting mosses, such as Leucodon sciuroides and Nogopterium gracile in Dinefwr Park and Zygodon rupestris at several sites.  Other epiphytes typical of mature ash trees include Frullania dilatata, Metzgeria furcata, Homalothecium sericeum, Hypnum resupinatum, Lewinskya affinis, L. striata, Pulvigera lyellii, and Zygodon viridissimus.  Oaks are usually less diverse, but sometimes support a similar assemblage; more often they are colonised by Dicranoweisia cirrata and Hypnum cupressiforme s.l.

The ground layer in stands of scrub is largely the same as in lowland woods.  Epiphytes are similar to those found on the hazel understorey, but may be more diverse.  Ulota phyllantha predominates in coastal scrub, declining to lower frequency inland and Myriocoleopsis minutissima shows a similar distribution, favouring coastal elder scrub.  Other regular species on elder include Metzgeria violacea, Lewinskya affinis, Orthotrichum diaphanum and Zygodon viridissimusMetzgeria violacea is also regular in stands of blackthorn, together with Frullania dilatata and Ulota bruchii.  Hawthorn, with its flaky acidic bark, tends to form bryophyte-poor scrub stands, but regularly supports Dicranoweisia cirrata and Hypnum cupressiforme.  Introduced sea buckthorn scrub in the Pembrey and Pendine dune systems is relatively diverse, whereas introduced butterfly-bush scrub in urban areas is poor.

Coniferous woodland

Acidophile mosses thrive on the floor of conifer plantations where heavy shade excludes vascular competitors.  Calypogeia fissa, Dicranella heteromalla, Hypnum jutlandicum, Kindbergia praelonga, and Pseudotaxiphyllum elegans are typical components of the ground layer of plantations throughout the vice-county, but upland plantations may support Saccogyna viticulosa, Rhytidiadelphus loreus and other species more typical of sessile oak woodland.  Most of these are thought to have persisted in situ from the habitats present prior to aforestation, rather than being more recent colonists.  Conifers are generally poor epiphyte hosts, although Hypnum andoi may festoon their twigs.  In contrast, willow trees shaded by conifers are often draped in bryophytes, including Colura calyptrifolia, Metzgeria furcata, M. temperata, Microlejeunea ulicina and Ulota crispa sl.

Tracks and banks often hold the greatest bryophyte diversity within a plantation.  The former supports a distinctive assemblage that includes Nardia scalaris, Solenostoma gracillimum, Bryum alpinum, Campylopus subulatus, Ditrichum heteromallum, Oligotrichum hercynicum, Pogonatum urnigerum and Pohlia annotina on more acidic tracks and Bryoerythrophyllum ferruginascens, Dicranella varia and Didymodon fallax where limestone is used for surfacing.  Several of the acidophiles, including J. gracillima, N. scalaris and D. heteromallum are equally characteristic of crumbling banks by tracks, together with Diplophyllum albicans and, on freshly exposed banks, D. obtusifolium.  Well-established banks support a similar range of mosses to those found on wet heath, including Sphagnum spp., Dicranum scoparium, Hylocomium splendens and Pleurozium schreberi.

Boundary and linear features

In many parts of the more intensively farmed countryside, hedges, ditches, walls, bridges and roadsides support most of the bryophyte diversity as improved pastures hold very few species.  Hedge banks support many of the same bulky pleurocarpous mosses that occur in lowland woods, such as Brachythecium rutabulum, Cirriphyllum piliferum, Kindbergia praelonga, Scleropodium purum and Thuidium tamariscinum.  Gaps in grassy hedge banks hold various Fissidens spp., including F. incurvus and F. viridulus, Weissia controversa and, in the southwest of the county, Epipterygium tozeriFossombronia pusilla is often present in soil gaps or on the side of ditches below hedge banks.  In more acidic situations, Diplophyllum albicans, Dicranella heteromalla, Dicranum scoparium, Hypnum jutlandicum and Pogonatum aloides are regular components of the hedge flora.  Where soils are more calcareous, Eurhynchium striatum and Hylocomiadelphus triquetrus can be prominent.

The epiphyte flora of hedges is often diverse, although it seldom includes notable species.  As in woodland, ash, elder, elm, hazel and sycamore are the principal host plants.  Branches within the hedge itself support Frullania dilatata, Metzgeria furcata, M. violacea, Radula complanata, Bryum capillare, Cryphaea heteromalla, Homalothecium sericeum, Zygodon viridissimus and several Orthotrichum and Ulota species.  Amblystegium serpens, Orthotrichum diaphanum and Rhynchostegium confertum tend to grow on elders, whilst Neckera complanata is often abundant when ash is a major component of the hedge.  Hedgerow trees, especially mature ash, characteristically support H. sericeum and Hypnum resupinatum and may have a rich array of ‘Orthotrichum’ spp., including Pulvigera lyellii, Orthotrichum stramineum and Lewinskya striatum.

Acidophiles, such as Dicranum scoparium, Hylocomium splendens and Pleurozium schreberi, grow on boundary banks in the uplands with Hypnum cupressiforme s.l. and Racomitrium spp. on blocks exposed within them and on walls.  Concrete gate-posts in the lowlands are colonised by the ubiquitous Tortula muralis and often Orthotrichum diaphanum, Grimmia pulvinata and Schistidium crassipilum.  Wooden gate- and fence-posts regularly have Campylopus introflexus or Dicranoweisia cirrata growing from their rotting tops.  Regularly cleared ditches provide damp, open soil on which Fossombronia pusilla, Pellia spp., Pseudephemerum nitidum, Tortula truncata and, more rarely, Riccia sorocarpa can maintain a foothold.

Arable and horticulture

Carmarthenshire’s agriculture is primarily pastoral, but there are a few mixed farms with arable fields, especially in the Trellech/Meidrim area and in the Tywi Valley.  Maize and root crops are relatively regularly encountered but support very poor bryophyte assemblages; cereal fields are scarcer and tend to be more diverse, but the practices of aftermath grazing and under-sowing with rye-grass reduce this diversity dramatically.  A few cereal stubble fields were examined during the BBS Survey of Bryophytes of Arable Land, which ran from 2002 to 2005.  These had pH varying between 5.5 and 6.8 and supported an assemblage of mosses and liverworts typical of south Wales’ neutral to acid arable land.  The most abundant species were Bryum rubens, Dicranella staphylina and Tortula truncata, whilst Fossombronia pusilla, other Bryum spp., Ephemerum serratum (formerly E. minutissimum) and Pleuridium subulatum were regular in smaller quantity.  The absence of Riccia glauca and R. sorocarpa from all but three fields is peculiar given their frequency in arable elsewhere in south Wales.  Weissia spp. were regular but few had mature sporophytes; W. longifolia var. longifolia was found on one farm and W. rostellata on another.  Other scarce species recorded from arable fields before SBAL include Anthoceros agrestis, Phaeoceros carolinianus and Riccia subbifurca, but it is probable that all of these and the Weissia spp. have declined, as few fields are left under stubble through the winter.

Carmarthenshire does not lend itself to farm-scale horticulture and the bryophytes of gardens will be discussed below.

Neutral grassland, including improved grassland

Unimproved or semi-improved dry pastures and hay-meadows may be rich in vascular plants and invertebrates, but they tend to be bryologically poor.  The bane of lawn-manicurists Rhytidiadelphus squarrosus is often abundant and Lophocolea bidentata, Brachythecium rutabulum, Calliergonella cuspidata, Kindbergia praelonga, Plagiomnium affine, P. undulatum and Pseudoscleropodium purum all occur regularly, but few bryophytes of any real interest are found in neutral grassland in Carmarthenshire.  Steep pastures and banks sometimes hold notable species, such as Anthoceros punctatus, Bryum donianum and Fissidens exilis on soil gaps, as well as Pleuridium acuminatum and Pseudephemerum nitidum.  Shiny mixtures of perennial rye-grass and crested dog’s-tail are consistently poor, although gappy swards may support a few mosses more typical of arable land.

Calcareous grassland

Most of the lowland calcicolous grassland on the limestone ridge was quarried away in the past or has become neglected and rank or invaded by scrub, so unimproved calcicolous grassland survives only on a few banks and in the uplands of Mynydd Du.  Bryophytes are often a prominent component of the sward, with pleurocarpous species, such as Calliergonella cuspidata, Ctenidium molluscum, Eurhynchium hians and Hypnum lacunosum, locally abundant.  Mesoptychia turbinata, Aloina aloides, Bryum pallens, Dicranella varia, Didymodon fallax and Ditrichum gracile can be frequent on steeper banks, together with Trichostomum crispulum in disused quarries.  Calcicolous grassland that has developed over limestone quarry spoil may be very rich, supporting Mesoptychia badensis, Lophozia excisa, Scapania cuspiduligera, Distichium inclinatum, Mnium stellare and Thuidium affine amongst others.

The limestone quarries of Foel Feddau are home to diverse bryophytes, including Scapania cuspiduligera

Acid grassland & bracken

Pleurocarpous mosses are regular components of acid swards, the most regular being Hylocomium splendens, Hypnum jutlandicum, Pleurozium schreberi, Rhytidiadelphus squarrosus and Thuidium tamariscinum.  Damper swards may approach wet heath in appearance, with scattered Aulacomnium palustre, Polytrichum commune and Sphagnum spp.  Stands of bracken often have such a dense layer of litter on the ground that no bryophytes can survive.  A few pleurocarpous mosses, including Kindbergia praelonga and Scleropodium purum, sometimes occur.

Dwarf shrub heath

Most of the county’s heathland is in the uplands, but relict stands are widespread in the lowlands as well.  Mosses are often prominent but seldom diverse in dry heath: Dicranum scoparium, Hylocomium splendens, Hypnum jutlandicum and Pleurozium schreberi are the principal species involved.  Diversity increases dramatically in wet heath, where a range of Sphagnum spp., including S. denticulatum, S. subnitens and S. tenellum, grow, providing a microhabitat for liverworts such as Calypogeia fissa and Cephalozia bicuspidata and the mosses Aulacomnium palustre and Polytrichum commune are locally abundant.  Humid north-facing slopes on Mynydd Mallaen hold a particularly bryophyte-rich form of dwarf shrub heath, with locally frequent Orthocaulis floerkei, Diplophyllum albicans, Ptilidium ciliare, Tritomaria quinquedentata, Breutelia chrysocoma, Rhytidiadelphus loreus and occasional Lophozia ventricosa and Dicranum majus.

Fen, marsh and swamp

This broad category includes most of the county’s lowland wetlands and also many upland habitats.  Calliergonella cuspidata is probably the most frequently-encountered moss in lowland marshy grassland, but Lophocolea bidentata, Brachythecium rutabulum and Kindbergia praelonga also occur regularly.  Tussocks of Molinia support a range of species, including Calypogeia arguta, C. fissa, Cephalozia bicuspidata, E. praelongum, Plagiothecium denticulatum and Pseudotaxiphyllum elegansBrachythecium rivulare and Calliergon cordifolium occur in wetter marshy grassland and poor-fen, but swamps and tall-herb fens tend to be too dominated by vascular plants to support many bryophytes except for occasional Riccardia chamedryfolia, Pseudocampylium radicale and Oxyrrhynchium speciosum on the coastal fringe.  Basin mire fens, such as those in pingos, hold poor-fen bryophytes that include Sphagnum fallax, S. papillosum, S. squarrosum and Sarmentypnum exannulatum.

Springheads and flushes have enormously varied bryophyte floras depending on the pH and mineral content of their water.  The most calcium-rich, as below the Foel Fawr quarries, are tufaceous and hold Mesoptychia badensis, Marchantia quadrata, Campylium stellatum, Cratoneuron filicinum, Ctenidium molluscum, Hymenostylium recurvirostrum and Scorpidium cossonii, as well as a little Moerckia flotoviana.  Many of these species are abundant in the typical base-rich flushes of the Old Red Sandstone hills, including C. stellatum, C. filicinum and S. cossonii, together with Aneura pinguis, Bryum pseudotriquetrum s.l. and Sarmentypnum sarmentosumPalustriella commutata sometimes dominates base-rich flushes or springheads, as do Jungermannia exsertifolia and Scapania undulata in more stony rills, whilst Calliergon giganteum, Scorpidium revolvens and S. scorpioides can all be locally abundant.  Hamatocaulis vernicosus and Sarmentypnum exannulatum favour water with a lower pH, often with Dichodontium palustre, Philonotis fontana, Sphagnum inundatum, S. subnitens or S. teres among the associates.  Sphagnum is the dominant genus in truly acidic conditions: S. denticulatum, S. fallax, S. fimbriatum and S. palustre are regular components of acid flushes, together with Straminergon stramineum and Polytrichum commune.

Hamatocaulis vernicosus is locally abundant in neutral mires in upland Carmarthenshire


Carmarthenshire holds a good number of bogs, although none rival those of Cardiganshire in either size or bryophyte diversity.  They occur primarily in the uplands and along the quartzite ridge and are generally only moderately Sphagnum-rich, with S. capillifolium, S. cuspidatum, S. denticulatum, S. fallax and S. papillosum the key species.  Sphagnum tenellum is restricted to a few species-rich bogs and S. magellanicum is known only from three sites.  Aulacomnium palustre and Polytrichum commune are often prominent, whilst the pleurocarpous mosses of heathland can be abundant on hummock tops.  There are usually liverworts, such as Calypogeia spp., Cephalozia bicuspidata, C. connivens, Cephaloziella hampeana, Odontoschisma fluitans, Kurzia pauciflora, Mylia anomala and Odontoschisma sphagni, growing over the Sphagnum, although they can be restricted to a few Sphagnum hummocks on some bogs.  Where the typical bog hummock and hollow structure is well-developed, as at Cors Goch Llanllwch, bryophytes are distributed along the hydrological gradient.  Thus, O. fluitans and S. cuspidatum grow in wet hollows; Kurzia pauciflora and Mylia anomala are abundant on the lower part of hummocks; Odontoschisma sphagni grows higher up on the hummocks; and Sphagnum tenellum is found primarily on the hummock tops.

Standing water

Riccia fluitans is the only Carmarthenshire bryophyte that floats on standing water: doing so at a few ox-bow pools in the Tywi and Tâf valleys and in ditches and pools on the Llanelli levels.  A few more, such as Fontinalis antipyretica and Leptodictyum riparium sprawl into pools from surrounding tree bases or logs.  Pools and reservoirs are transformed into potentially rich bryophyte habitats, however, when they dry out.  Physcomitrium pyriforme is occasional on the mud of dried-out pools in the lowlands, whilst its rare congener P. sphaericum grows at Cwm Lliedi Reservoir.  Another closely related species, Aphanorregma patens, grows there and at the Pant-y-llyn turlough, where a rich assemblage also includes Riccia cavernosa, Bryum klinggraeffii, Ephemerum Ephemerum crassinervium subsp. rutheanum (formerly E. hibernicum), E. stoloniferum (formerly E. serratum) and Pseudephemerum nitidumEphemerum stoloniferum also colonises bare mud by Usk Reservoir, where the pH is lower, together with Fossombronia foveolata, F. wondraczekii, Scapania irrigua, Archidium alternifolium and Philonotis fontana.

Rivers and streams

In upland Carmarthenshire, most streams and rivers are rocky and rich bryophyte assemblages develop on the rocks.  Typical species include Marsupella emarginata, Campylopus atrovirens, Fontinalis squamosa, Racomitrium aciculare, Sciuro-hypnum plumosum and Schistidium rivulare and these are joined by abundant Isothecium holtii in a few places and Racomitrium macounii on the upper Tywi.  Heterocladium wulfsbergii and Platyhypnidium lusitanicum are characteristic of rocks in deeply shaded streams, especially in gorges.  Gritty ledges by these streams may also support a variety of Solenostoma species, including S. hyalina, S. obovata and S. paroica.   The middle reaches of rocky rivers hold a similar range of species, such as Chiloscyphus polyanthos, Porella pinnata, Scapania undulata, S. plumosum, Fontinalis antipyretica, F. squamosa and R. aciculare.  On a few rivers, Fissidens monguillonii, F. rivularis and F. rufulus occur on rocks at or just below normal water levels.  Riverside shelves are usually carpeted with bryophytes, including most of those found on rocks in the river as well as Dichodontium sp., Kindbergia praelonga, Plagiomnium rostratum, Rhizomnium punctatum and Thamnobryum alopecurum.  The large thallose liverworts Conocephalum conicum s.l. and Lunularia cruciata favour soil slightly further up the bank.  The most acidic streams, particularly on the upland Carboniferous sandstones, hold abundant Nardia compressa and few other bryophytes.

The lower reaches of the Afonydd Tâf and Tywi have steep soil banks on which a quite different assemblage of bryophytes grows.  Most of these are small mosses that either reproduce using tubers or fruit rapidly and abundantly.   Typical members include Bryum dichotomum, B. gemmiferum, Epipterygium tozeri, Pleuridium acuminatum, P. subulatum, Pohlia melanodon, Pseudephemerum nitidum, Tortula truncata and Trichodon cylindricus.  The Gwendraeth rivers have a character more akin to that of English rivers and hold more frequent calcicoles, such as Cinclidotus fontinaloides and Fissidens crassipes, as well as the locally rare Dialytrichia mucronata and Schistidium platyphyllum.

The epiphyte flora of the frequently flooded lower trunks of alders and willows by the Afonydd Tâf, Teifi and Tywi includes Cirriphyllum crassinervium. Leskea polycarpa, Orthotrichum rivulare, O. sprucei and Syntrichia latifolia with, higher up the trunks, species less tied to water, such as Frullania dilatata, Metzgeria furcata, Hypnum cupressiforme, Lewinskya affinis, Pulvigera. lyellii, Ulota bruchii and U. phyllanthaDendrocryphaea lamyana is a speciality of the Afon Teifi that usually grows epiphytically in Carmarthenshire, although it is more abundant on sunny rocks on the Ceredigion bank of the river.

The Afon Tywi is a silty, mature river downstream of Llandeilo

Montane habitats

The habitats that dominate the Carmarthenshire uplands – acid grassland, bog and heath – have been discussed above, as have the rocky streams that cut through them.  The crags and ledges of Bannau Sir Gaer and the block screes of Mynydd Du and Mynydd Mallaen are, then, our most characteristically upland habitats.

The Old Red Sandstone of Bannau Sir Gaer varies considerably in pH.  Damp acid rocks predominate, especially near the top of the crags, but there are also extensive outcrops of base-rich sandstone.  Marsupella emarginata, Andreaea rothii subsp. falcata, Racomitrium aciculare, R. aquaticum, R. fasciculare and Polytrichastrum alpinum are the most abundant bryophytes on flushed, acid faces, which tend to be rather species-poor.  Recesses in these faces hold Diplophyllum albicans, Mnium hornum, Pseudotaxiphyllum elegans and a few others.  In contrast, a wide range of species occur on more base-rich faces, including Frullania tamarisci, Lejeunea patens, Anoectangium aestivum, Blindia acuta, Bryoerythrophyllum ferruginascens, B. recurvirostrum, Ctenidium molluscum, Grimmia torquata, Gymnostomum aeruginosum (sometimes with Jungermannia borealis growing on it), Schistidium strictum and Tortella tortuosa.  Crevices and overhangs on base-rich rock support the greatest diversity, with cushions of Amphidium lapponicum, A. mougeotii and Anoectangium aestivum holding thin stems of Blepharostoma trichophyllum, L. patens and Isopterygiopsis pulchella; occasional Plagiochila spinulosa, Bartramia ithyphylla, Plagiobryum zieri, Pohlia cruda, P. elongata, Fissidens adianthoides, F. osmundoides, Mnium marginatum and Blindiadelphus recurvatus (Seligeria recurvata); and a few rarities such as Mesoptychia heterocolpos, Scapania aequiloba and S. gymnostomophilaEncalypta ciliata, Schistidium apocarpum and S. crassipilum tend to grow on top of bluffs or sandstone boulders on the crag, whilst Grimmia trichophylla, S. apocarpum and Tortella bambergeri thrive on blocks below the crag.  Steep slopes below the crags are clothed in acid grassland that holds abundant pleurocarpous mosses.  Chutes of friable soil cut through this and are colonised by Nardia scalaris, Ditrichum heteromallum, Oligotrichum hercynicum and Pogonatum urnigerum.

Orange-tinged Schistidium strictum on Bannau Sir Gaer

Racomitrium lanuginosum is usually the most abundant bryophyte in Carmarthenshire’s upland block scree, although it can be rivalled for abundance by Andreaea rothii subsp. falcata.  These two mosses, and also Dicranoweisia cirrata, are able to tolerate exposure, so grow on top of rocks as well as on their sides.  Diplophyllum albicans also plasters the side of rocks, whereas most other scree-bed species, such as Cephaloziella divaricata, Gymnocolea inflata, Lophozia ventricosa, Scapania gracilis, Campylopus flexuosus, Pohlia nutans, Polytrichastrum alpinum and Polytrichum formosum, are restricted to holes between blocks.  The massive block scree on the north side of Mynydd Mallaen supports frequent Mylia taylorii and occasional Douinia ovata, northern species near the southern edge of their British range, as well as Sphenolobus minutus (Anastrophyllum minutum), Orthocaulis attenuatus, Bazzania trilobata, Scapania gracilis, Dicranum fuscescens, Heterocladium heteropterum and Hypnum andoi.

Inland rock

Stream gorges in woodland are among the vice-county’s richest bryophyte habitats.  Gorges tend to provide a microclimate that is both cooler and more humid than their surroundings so they can support species that require humid conditions, even in southern Carmarthenshire where rainfall levels are rather low.  The most diverse gorges are in the Mynydd Mallaen area.  Most of the outcropping Silurian rock is rather acidic and supports relatively common species, such as Diplophyllum albicans, Marsupella emarginata, Cynodontium bruntonii and Heterocladium heteropterum.  However, some of the sandstones there have lime-rich cements and support a dramatically more diverse bryophyte flora.  Typical of these areas are Frullania tamarisci, Plagiochila spinulosa, Amphidium mougeotii, Fissidens adianthoides, F. dubius, F. osmundoides, Neckera crispa, Tortella tortuosa and Trichostomum brachydontium.  A few gorges also hold colonies of scarce or biogeographically notable species, including Cololejeunea microscopica (Aphanolejeunea microscopica), Frullania fragilifolia, Harpalejeunea molleri, Lejeunea patens, Metzgeria leptoneura, Plagiochila bifaria, P. exigua, Porella arboris-vitae and Bartramia halleriana. Elsewhere in the county, there are widely scattered colonies of Jubula hutchinsae, M. conjugata, P. spinulosa and P. punctata, almost wherever a gorge is sufficiently deep to hold humidity all year round.  Lejeunea lamacerina is often abundant in small rocky gullies near the coast, as at Marros Mill and north of Kidwelly, and sometimes has Lophocolea fragrans growing through it.

Plagiochila spinulosa is a locally abundant liverwort of oceanic ravines

Natural sandstone crags and bluffs in woodland tend to be acidic and dominated by Diplophyllum albicans, but other species, such as Marsupella emarginata, Bartramia pomiformis and Oreoweisia bruntonii, are locally frequent.  As in the Mynydd Mallaen gorges, base-enrichment greatly enhances the flora of a crag, providing suitable conditions for Marchesinia mackaii, Plagiochila bifaria, Porella arboris-vitae, Sphenolobopsis pearsonii, Ctenidium molluscum, Grimmia torquata, Neckera crispa, Tortella tortuosa and Trichostomum brachydontium, at least in the county’s north-east.  Wooded road cuttings in the hill country, as near Meidrim, Cynwyl Elfed and Alltwalis, are probably a mix of natural and quarried faces.  Their bryophyte flora is moderately rich and includes a range of characteristic species, including B. pomiformis, Diphyscium foliosum and Racomitrium affine.

The paucity of shaded natural limestone in Carmarthenshire is reflected in the vice-county’s rather short list of Seligeria spp.  Porella platyphylla, Anomodon viticulosus, Mnium stellare, Neckera crispa, Tortella tortuosa and Trichostomum brachydontium are among the typical bryophytes of the natural limestone at Carreg Cennen, the valley west of Pendine and a few spots around Carmel.  Large rocks below these outcrops are carpeted in pleurocarpous mosses, including Brachythecium rutabulum, C. molluscum, Eurhynchium striatulum, Homalothecium sericeum and Isothecium alopecuroides, whilst smaller pieces of limestone hold Fissidens pusillus, Taxiphyllum wissgrillii or, at Carreg Cennen, the rarities Serpoleskea confervoides and Blindiadelphus (Seligeria) cf. campylopoda.

There are rather few unwooded natural exposures of sandstone apart from those on Mynydd Du.  When such conditions do occur elsewhere, as near Llyn Brianne, characteristic species include Grimmia trichophylla, Hedwigia stellata and Nogopterium gracile.  The Grimmia and Nogopterium also grow on the large sandstone blocks that are scattered across Mynydd y Llan and Mynydd Myddfai, together with Frullania tamarisci, Schistidium crassipilum and Tortella bambergeri.  The tiny Seligeria acutifolia is characteristic of natural limestone outcrops on Mynydd Du, growing in crevices almost wherever faces have been left unquarried.  Scapania aspera, Bryum pallens (including the gemmiferous ‘subelegans’ form), Encalypta streptocarpa and Neckera crispa are among the other typical species of these outcrops and Conocephalum salebrosum was recorded there recently.  Most of the natural pavement on the limestone ridge has been damaged, but a few natural areas remain.  Syntrichia montana, Tortella nitida and Tortula muralis tend to favour the flatter, more exposed parts of these pavements, whilst Fissidens dubius, Homalothecium sericeum and Tortella tortuosa hide in the grykes.

Most beds of block scree are in the uplands, but at Carn Goch there are extensive areas below 300 m altitude.  Like their upland counterparts, these hold Lepidozia reptans, Scapania gracilis, Campylopus flexuosus, Pohlia nutans, Pseudotaxiphyllum elegans, Racomitrium lanuginosum and rare Lepidozia cupressina.  More remarkable are beds of Millstone Grit scree on the coast at Ragwen Point near Pendine and at Woodreefe, inland of Marros.  Typical bryophytes they hold include L. reptans, S. gracilis, C. flexuosus, P. elegans and Isothecium myosuroides but the former also supports a disjunct colony of Plagiochila punctata, scattered Bazzania trilobata, locally frequent Frullania fragilifolia and a few patches of Grimmia decipiens.

The secondary faces of quarries often support a good range of bryophytes, especially where there is superficial flushing.  However, they seldom if ever hold the notable species that grow on natural faces.  There are numerous small or medium-sized sandstone and shale quarries in the hill country and the uplands.  The ubiquitous calcifuge bryophytes Diplophyllum albicans, Dicranella heteromalla, Mnium hornum and Pseudotaxiphyllum elegans are the most regular colonists of disused faces, whilst Brachythecium rutabulum, Bryum capillare and Eurhynchium praelongum cover shaded rocks on the floor.  A little seepage of base-rich water is enough to encourage Rhynchostegium riparioides and slightly more may provide suitable conditions for Fissidens adianthoides.  Insolated areas support a different range of species, including D. albicans, Nardia scalaris, Pogonatum urnigerum, Polytrichum juniperinum, P. piliferum and Racomitrium heterostichum.  Limestone quarry faces are colonised by common calcicoles, such as Tortula muralis and, where wet, Eucladium verticillatumEncalypta streptocarpa, Grimmia pulvinata, Orthotrichum anomalum, Schistidium crassipilum, Syntrichia intermedia and T. muralis are among the mosses that are abundant on blocks on limestone quarry floors.  The damp, gravelly floor of quarries on the Carmel Ridge often has abundant Didymodon ferrugineus, as well as Mesoptychia badensis, Didymodon fallax, Ditrichum gracile and E. streptocarpa.  Mounds of limestone quarry spoil usually support sufficient vascular plants to be considered secondary calcareous grassland, as discussed above.  A rich array of Grimmia spp. grow in the Dolerite quarry at Llangynog, as well as a strange mix of calcifuge and calcicole mosses, such as Dicranoweisia cirrata, Racomitrium heterostichum and Tortula muralis.  The damp gravelly floor is dominated by Campylopus introflexus and Polytrichum piliferum but also holds Cephaloziella spp., Fossombronia incurva and Lophozia excisa.

Carmarthenshire’s lead mines, concentrated in the north-east, are for the most part too small and too dry to support interesting bryophytes.  Mosses of dry acid rock, such as Grimmia donniana and Polytrichum piliferum, are usually the only bryophytes present.  The exceptions are Nant-y-bai and Nant y Mwyn mines near Rhandirmwyn, where Aneura pinguis, Cephaloziella spp. and Dicranella varia colonise damp spoil and Bryum pallescens, Ditrichum plumbicola, Scopelophila cataractae and Weissia controversa var. densifolia grow on the most toxic waste.  Most colliery spoil heaps are also too dry to support many bryophytes, although Polytrichum spp. and Racomitrium ericoides may occur.  However, where flushing occurs they can support a rich assemblage of species, such as A. pinguis, Bryum pseudotriquetrum, Cratoneuron filicinum, Didymodon fallax, D. tophaceus, Encalypta streptocarpa and Trichostomum crispulum.

Built up areas and gardens

The mosses of wall tops are among our most familiar bryophyte species.  Hoary cushions of Grimmia pulvinata, Schistidium crassipilum, Syntrichia montana and Tortula muralis are mixed with brown or green Didymodon rigidulus, Orthotrichum anomalum and, in the lowlands, Tortella nitidaBarbula sardoa, B. unguiculata, Bryum radiculosum, D. rigidulus, Encalypta streptocarpa, Pseudocrossidium revolutum and S. crassipilum follow lines of lime-rich mortar on wall faces, joined by Rhynchostegiella tenella where there is a little shade.  Homalothecium sericeum is often abundant on walls, sometimes accompanied by profuse Neckera complanata, especially on the shaded side of bridges.  Nitrophiles, such as Bryum argenteum and B. dichotomum gather at the base of walls, spreading outwards to colonise damp tarmac.  A wide range of mosses grows on tarmac, including most of the above species, Cratoneuron filicinum, Didymodon luridus, D. nicholsonii, Funaria hygrometrica, Syntrichia ruralis and sometimes S. latifolia.

Homalothecium sericeum, Hypnum cupressiforme s.l., Orthotrichum anomalum, Schistidium crassipilum and Syntrichia ruralis are among the wide range of mosses that grow on corrugated asbestos roofs.  Artificial tiles may support a similar range of species, but often appear to be lichen-dominated rather than mossy.  Natural stone tiles are uncommon in the county and the rich assemblage on tiles in Monmouthshire appears to be absent from Carmarthenshire.  Examination with a telescope suggests that Racomitrium fasciculare may be present on a stone tiled roof at Glynhir Mansion.  Campylopus introflexus is a regular colonist of slate roofs, usually in gaps between the slates.  The metalophytes Bryum pallescens and Weissia controversa find suitable conditions where metal-rich water drips off corrugated iron roofs on to walls or the ground; they are also frequent on bare soil below galvanised roadside crash barriers.

A typical suburban garden in Johnstown was found to hold 22 species of moss in 2001.  Most of these grew on walls, paths or the roof, but Brachythecium rutabulum and Calliergonella cuspidata were present in the lawn.  Gardens with flower beds may also hold mosses more typical of arable fields, such as Barbula unguiculata, Bryum rubens, Ephemerum serratum (formerly E. minutissimum), Fissidens taxifolius, Oxyrrhynchium hians and Tortula truncata, although regular hoeing seems to discourage them.  One remarkable garden in Llanelli even holds Phaeoceros laevisMarchantia polymorpha subsp. ruderalis and Leptobryum pyriforme are probably frequent in flower-pots in Carmarthenshire despite the scant records.

Supralittoral rock (including coastal slopes)

Cliffs run along the county’s coast at intervals between the Pembrokeshire border and Pendine, and at the end of the Llansteffan Peninsula.  They support a quite different assemblage of bryophytes to that elsewhere in the vice-county and show close affinities to Pembrokeshire.  The tallest cliffs, at Telpyn Point, are largely devoid of bryophytes, but Platyhypnidium riparioides thrives where there is a constant drip of water, together with Bryum pseudotriquetrum and, near Amroth, Campylopus fragilis and Weissia perssonii.  Most coastal slopes hold abundant Trichostomum brachydontium and sometimes some Tortella flavovirens or Tortula viridifolia.  Outcropping rock usually has Frullania tamarisci or Hypnum resupinatum growing on it, and the latter can also be abundant on stunted oaks on cliff-tops.  Bryum dichotomum dunense’, Didymodon tophaceus and Hennediella heimei grow on damper slumps behind Marros Sands, whilst Gymnostomum viridulum is abundant on more calcareous damp slopes at Craig Ddu.  Lower bluffs of rock around Laugharne and Llansteffan provide suitable conditions for Schistidium maritimum, with Frullania microphylla, Lejeunea lamacerina, Scorpiurium circinatum, Syntrichia laevipila and T. brachydontium in slightly more sheltered places and T. viridifolia in pockets of soil.

The Old Red Sandstone of the coast near Llansteffan

Supralittoral sediment

Saltmarsh forms much of the littoral around the three rivers and in the Burry Inlet, whilst dune systems have built up between Pendine and Laugharne, between Kidwelly and Pembrey and in a few other places.  The halophyte Hennediella heimei is the only moss that appears regularly in Carmarthenshire’s saltmarshes, favouring bare soil in their upper reaches.  Tortula caucasica (T. modica) is an occasional associate near Llanelli, notably on soil surrounding mounds of rubble in the saltmarsh, and Bryum marratii occurs in saltmarsh on the north side of Pembrey Burrows.  The saline-influenced edge of the Pembrey dune system supports Amblystegium serpens var. salinum and Tortella flavovirensSyntrichia ruraliformis is abundant on drier dunes, with various associates such as Barbula unguiculata, Brachythecium albicans, Bryum algovicum and Rhynchostegium megapolitanum.  Much of the slack vegetation has been lost to scrub encroachment, but remaining open slacks support abundant Calliergonella cuspidata and Drepanocladus aduncus and lesser amounts of Bryum pseudotriquetrum, Kandaea elodes (Campyliadelphus elodes), Campylium stellatum, Cratoneuron filicinum, Scorpidium cossonii and Drepanocladus polygamus.  The liverworts Aneura pinguis and Pellia endiviifolia and the moss Dicranella varia are frequent on bare damp sand and are joined at Pendine by Moerckia flotoviana and Petalophyllum ralfsii.  The scarce moss Amblyodon dealbatus persists in small quantity at Pembrey, whilst Abietinella abietina is still present at Pendine.

Key sites for bryophyte conservation in Carmarthenshire

Notable bryophytes have been recorded at numerous localities across the entire vice-county and are doubtless present at many others.  Twelve sites, some of them parts of more extensive key areas, stand out as being particularly important for bryophyte conservation in Carmarthenshire.  Most are protected by SSSI and/or SAC designations, but two (Brechfa Forest and Pont ar Wysg) are not and not all of the bryophyte-rich sections of the coastal sites are protected either.  They are listed below in approximate Grid Reference order and the most interesting species at each key site are mentioned.  Many other sites are of significant bryophyte conservation importance and their exclusion from this list certainly does not mark them as unimportant.  Most of these are mentioned in subsequent paragraphs covering key bryophyte habitats in the vice-county.

The Marros-Pendine coast (SN10 & SN20)

The Marros coast near Telpyn Point

The coast between the village of Pendine and the border with Pembrokeshire has a character more typical of that county than the rest of Carmarthenshire.   A few scarce species that are relatively frequent on the Pembrokeshire coast, such as Frullania microphylla, Coscinodon cribrosus, Tortula viridifolia and Weissia perssonii, are found here, together with Archidium alternifolium, Campylopus fragilis, Pogonatum nanum, Tortella flavovirens and a disjunct colony of Entosthodon attenuatus.  Millstone Grit block scree on the east side of Ragwen Point supports several cushions of Grimmia decipiens, a moss first found there by HH Knight, who also noted Ulota hutchinsaeFrullania fragilifolia is frequent in the lower part of the scree, whilst some of the deeper holes hide Bazzania trilobata and Plagiochila punctata.  In contrast, calcicolous bryophytes grow on the limestone of Gilman Point and Dolwen Point; they include Encalypta vulgaris, known there since Knight’s time, Reboulia hemisphaerica, Bryum donianum, Gymnostomum viridulum, Microbryum davallianum and Tortula lindbergii (T. lanceola).

Pendine Burrows (SN20 & SN30)

Kandaea elodes growing alongside Equisetum variegatum in the Carmarthenshire dunes

The principal bryophyte conservation interest at Pendine Burrows is the population of Petalophyllum ralfsii that persists in a few slacks.  The population was believed to be declining in the early 2010s, but a 2020 survey has shown a significant increase in three areas.  Kandaea elodes, Didymodon acutus, Drepanocladus sendtneri, Moerckia flotoviana and Riccia cavernosa also grow in the slacks, whilst Abietinella abietina and Tortella squarrosa occur in base-rich dune grassland.  The closing-over of slacks due to the lack of recent grazing may have caused the disappearance of these two mosses and continued management is essential to maintain the colonies of the three liverworts.

The Laugharne coast (SN20 & SN30)

Sir John’s Hill, Laugharne: locus for Habrodon perpusillus

Mediterranean-Atlantic bryophytes are better represented in the Laugharne area than in any other part of the vice-county.  Most grow on the south-facing sandstone cliffs that stretch from Honey Corse around to Laugharne village, including Targionia hypophylla, Grimmia lisae, Scorpiurium circinatum, Tortella nitida and Tortula viridifolia.  This sandstone is also the habitat for one of the two Carmarthenshire colonies of Frullania microphylla, whilst thin soil overlying an outcrop supports Riccia subbifurca.  One of only five known Welsh colonies of the Red Data Book Habrodon perpusillus is on ash and sycamore trees on the crags west of Salt House.  Further Mediterranean-Atlantic species grow in Laugharne itself: Dialytrichia mucronata near Dylan Thomas’s Boathouse and, north of the village, Cephaloziella turneri and Ditrichum subulatum on the crumbly overhanging estuary bank.  An unusual feature of the area is the presence of Syntrichia laevipila and S. papillosa growing on sandstone as well as epiphytically.

Afon Teifi (SN24 to SN54)

The Afon Teifi at Cennarth

Although one very rare species, Dendrocryphaea lamyana, is synonymous with the Afon Teifi for many bryologists, the river holds a rich supporting cast.  Tree trunks in the lower reaches of the river support Orthotrichum sprucei, whilst Porella pinnata grows on their roots; sandstone outcrops hold Grimmia lisae, Isothecium holtii and Nogopterium gracile. Porella cordaeana has its only known extant VC44 population below Cenarth Bridge.  The Dendrocryphaea has been found at seven localities on the Carmarthenshire bank of the river, all of them downstream of Maesycrugiau.  A few other uncommon bryophytes grow in the Teifi valley, including Philonotis arnellii at Plasgeler, Leucodon sciuroides at Pont Bargod and colonies of Bazzania trilobata, Jubula hutchinsae and Plagiochila spinulosa in humid woodlands.

Brechfa Forest (SN43 & SN53)

An ash trunk in Cwm Marydd, Brechfa supporting Plagiochila exigua

Brechfa Forest holds many areas of good bryophyte habitat hidden amongst its extensive conifer plantations and is particularly notable for humidity-demanding species more typical of the Mynydd Mallaen area.  Sandstone crags and steep-sided valleys provide suitable conditions for the more interesting bryophytes; such conditions occur in the valleys of the Afon Pib, Nant Cwm-marydd, Nant y Ffin and Afon Gorlech as well as by the Afon Cothi.  Frullania fragilifolia, Campylopus atrovirens and Entosthodon obtusus are notably disjunct in the Afon Pib valley.  Tritomaria exsecta is at its only known Carmarthenshire site on a log by the Nant Cwm-marydd, Platyhypnidium lusitanicum grows in the stream and Plagiochila exigua is on two ash trunks nearby. Cwm Marlais holds frequent Cololejeunea microscopica on riverside ash trunks, and Drepanolejeunea hamatifolia has been found on two trees in the plantations north-west of Brechfa. The Hyperoceanic moss Daltonia splachnoides has also been found once on willows here.  The Nant y Ffin valley holds Syzygiella autumnalis (Jamesoniella autumnalis) and the only known Brechfa colony of Neckera crispa.  North of Abergorlech, Hygrobiella laxifolia and Lophocolea fragrans are present on riverside rocks, whilst Heterocladium wulfsbergii grows to the south of the village by the Afon Cothi.  Colura calyptrifolia, Jubula hutchinsae, Metzgeria conjugata, Plagiochila punctata and P. spinulosa are widely scattered in the area.

Carreg Cennen (SN61)

Open hazel-ash woodland below Carreg Cennen Castle

Carmarthenshire is not blessed with many natural limestone crags and Carreg Cennen is much the best example of this habitat in the county.  Bryum canariense, collected new for the county in 2010, is the most notable species here.  Five other tiny calcicoles were discovered previously: Serpoleskea confervoides and a short-leaved Seligeria sp. (potentially Blindiadelphus campylopodus) on small pieces of limestone, and Gymnostomum calcareum, S. acutifolia and S. pusilla in crevices at the west end of the crags.  Eurhynchium striatulum is remarkably abundant at the foot of the crags and on limestone boulders, as is Anomodon viticulosus, which is otherwise uncommon in Carmarthenshire.  The presence of Plagiomnium cuspidatum is also noteworthy.

Clogau Mawr and Foel Fawr (SN71)

Lime-rich tufa flushes on Foel Fawr

The long history of limestone quarrying on Mynydd Du has resulted in a good range of calcareous habitats set in an area of acidic moorland.  There are few natural limestone faces, most having been exposed or damaged by quarrying, but most of those which remain support Seligeria acutifolia.  Most of the area’s rarest species grow on quarry spoil heaps, on the damp floor of the quarries or in tufaceous flushes spreading down the hillsides.  These include Solenostoma confertissimum at its only known Welsh site, Moerckia flotoviana, Scapania cuspiduligera, Bryum concinnatum and Distichium inclinatum.  Hymenostylium recurvirostrum, a scarce species in south Wales, is locally dominant in some of the tufaceous flushes and sometimes has Amblyodon dealbatus or M. flotoviana growing out of it.  Jean Paton found Blasia pusilla, Fossombronia incurva, Riccardia incurvata and Pohlia filum in a damp hollow below the road in 1969, probably in a less calcareous situation than those favoured by the previous species.

Bannau Sir Gaer (SN72 & SN82)

The crags of Bannau Sir Gaer are one of the most iconic views of Carmarthenshire

More bryologists have visited the crags of Bannau Sir Gaer, above Llyn y Fan Fach, than any other site in the vice-county.  Nevertheless, species have been added to the county list on every recent visit, an indication of the site’s exceptional richness.  The sandstone here varies in pH, with relatively base-rich rock supporting scarce upland calcicoles and acidic rock holding a few montane calcifuge mosses well south of their core ranges.  Scapania gymnostomophila is the rarest bryophyte recorded on the crags as no other south Wales colonies are known.  Jungermannia borealis, Mesoptychia heterocolpos, Scapania aequiloba, S. lingulata, Amphidium lapponicum, Bryoerythrophyllum ferruginascens, Encalypta ciliata and Schistidium strictum are among the other notable calcicoles.  Isothecium myosuroides var. brachythecioides and Ditrichum zonatum var. zonatum are both rare in south Wales as a whole, whilst Andreaea alpina, Oedipodium griffithianum and Pohlia flexuosa are also biogeographically notable.  The rich supporting cast on the crags includes Brachydontium trichodes, Distichium capillaceum, Grimmia torquata, Isopterygiopsis pulchella, Orthothecium intricatum and Bryum zieri.  A very strong colony of Tortella bambergeri occupies sandstone boulders by the stream below Llyn y Fan Fach, Sphagnum russowii grows on a flushed bank by the access track and Moerckia flotoviana is in at least one stony flush.  Knight’s colony of Porella cordaeana has not yet been relocated.

Pont ar Wysg (SN82)

Mawnbwll Du Mawr bog is fenced off from the surrounding moorland near Usk Reservoir

The moorland of Mynydd Myddfai and Mynydd y Llan is typified by the area around Pont ar Wysg which holds good flush, bog and crag habitats as well as the braided upper reaches of the Afon Wysg.  An unusual assemblage of scarce liverworts, not repeated elsewhere in the county, occurs on fine gravel by the river.  Fossombronia fimbriata is the rarest member of the assemblage as Blasia pusilla, Fossombronia incurva and Haplomitrium hookeri are found at a handful of other Carmarthenshire sites.  Hamatocaulis vernicosus is locally abundant in flushes, together with Calliergon giganteum, Plagiomnium elatum and P. ellipticum.  The fenced-off bog of Mawnbwll-du-mawr holds Sphagnum magellanicum.  Sandstone rocks scattered across the moorland support Nogopterium gracile and Tortella bambergeri, whilst a boulder near the top of Cwm Clydach holds a small colony of Encalypta ciliata.  Cwm Clydach is also notable for the presence of Plagiochila bifaria, P. punctata, Porella arboris-vitae, Hedwigia stellata and Philonotis caespitosa.

Cothi Gorge (SN74)

Base-rich rockfaces in the Cothi Gorge, supporting Harpalejeunea ovata and Plagiochila exigua

The gorge near the head of the Afon Cothi is the most bryophyte-rich, and also the most precipitous, of those in the Mynydd Mallaen area.  These two factors are linked, as the vertical walls provide constantly humid conditions, with base-rich Middle Llandovery Series rock enhancing the situation.  Metzgeria leptoneura and Harpalejeunea ovata are the most notable species in the gorge.  The former, at its southernmost British locality, is present as one small patch, but the latter is abundant on one rock face.  The same face supports Plagiochila bifaria and P. exigua as well as Neckera crispa, which shows the calcareous nature of the rock; Metzgeria conjugata, Plagiochila spinulosa and Porella arboris-vitae are nearby.  Other humidity-demanding species grow closer to the Afon Cothi, including Jubula hutchinsae, Lophocolea fragrans, Solenostoma obovatum, Heterocladium wulfsbergii and Platyhypnidium lusitanicum.  Several sections of the gorge are inaccessible without ropes and it is likely that other notable species remain undetected.

Creigiau Ladis (SN74)

Block scree on the north side of Mynydd Mallaen at Crugiau Ladis

The extensive block scree fields on the north-facing slopes of Mynydd Mallaen are important for the number of humidity-demanding species they hold.  Knight explored this area and recorded Barbilophozia barbata, Douinia ovata, Andreaea alpina, Dicranum scottianum and Rhabdoweisia crenulata.  Although three of these species have not been relocated, two remain, and Douinia, at least, is frequent.  More recent explorations have also revealed Calypogeia neesiana and Gymnomitrion crenulatum at their only Carmarthenshire site as well as abundant Mylia taylorii and frequent Sphenolobus minutus, Lepidozia pearsonii, and Dicranodontium denudatumLepidozia cupressina, Kurzia trichoclados, Scapania umbrosa and Sphagnum girgensohnii are also present, Blasia pusilla grows on slumped soil, and it is likely that Marsupella funckii and Ditrichum lineare, present elsewhere in similar habitat, have been overlooked here.

Dinas and Rhuddallt (SN74)

The rocky Afon Tywi in Dinas RSPB reserve

The RSPB’s Dinas reserve, surrounding the cave of Ystafell Twm Shon Cati, and the privately owned Rhuddallt, a little further up the Tywi Valley, are outstanding examples of ‘Atlantic’ woodlands enhanced by base-rich rock outcrops.  The rarest species in the area, Racomitrium macounii subsp. alpinum is frequent on rocks in the Tywi by both woods; Grimmia ramondii also grows by the Tywi at Dinas and Isothecium holtii is prominent on riverside rocks.  Several patches of Sphenolobopsis pearsonii, a strong colony of Plagiopus oederianus and several patches of Marchesinia mackaii, Bartramia halleriana and Grimmia torquata are highlights on the Rhuddallt rock-faces.  Those at Dinas are slightly less species-rich but hold M. mackaii, Plagiochila bifaria and Reboulia hemisphaerica.  Stunted oaks near the top of Rhuddallt support frequent Frullania fragilifolia, whilst fallen wood provides a substrate for a well-developed log flora, including Anastrophyllum hellerianum and Odontoschisma denudatum at Dinas, Blepharostoma trichophyllum at Rhuddallt and Tritomaria exsectiformis at both sites.  Typical ‘Atlantic’ species, such as Bazzania trilobata and Plagiochila spinulosa, are locally abundant in both woods.

Other sites

Various woods in the Mynydd Mallaen area have rich Oceanic bryophyte assemblages.  Species of particular note include Jamesoniella autumnalis at Allt yr Hebog (SN64); Sphenolobopsis pearsonii at Nant Melyn (this and all the rest SN74); Lepidozia cupressina below Craig Diferion; Cephalozia catenulata and Hygrohypnum eugyrium at Nant y Clun; Syzygiella autumnalis and Hypnum callichroum in Allt Gwenffrwd and C. catenulata, Plagiochila exigua, Bartramia halleriana and H. eugyrium at Allt Rhyd y Groes NNRAnastrophyllum hellerianum, Odontoschisma denudatum, Tritomaria exsectiformis and Dicranodontium denudatum grow on logs at most of these sites.

The Gwenffrwd Gorge near Mynydd Mallaen

Biogeographically, two southern woodlands are of particular note for the presence of outlying colonies of Oceanic bryophytes.  Bazzania trilobata and Plagiochila spinulosa grow on outcrops in oak woodland at Woodreefe Wood (SN10) and these two species occur with Sphagnum quinquefarium and abundant Kurzia sylvatica at Allt Troserch (SN50).

There are numerous stands of wet woodland in the county, but few of them hold notable bryophytes.  The exceptions are the birch carr between the two Talley Lakes (SN63), where Aneura mirabilis was dug up in 2004, and the alder carr at Middleton Hall (SN51) where Oxyrrhynchium speciosum grows.  Plagiomnium elatum and P. ellipticum, both of which are rare in Carmarthenshire’s lowlands, are found at Talley and Middleton Hall respectively.

Away from the main upland blocks, there are relatively large areas of moorland on Mynydd Llanllwni and Mynydd Llanybydder (both SN53) and a few smaller scattered remnants elsewhere.  The disjunct colony of Tritomaria quinquedentata on Mynydd Llanllwni is notable, as is the colony of Sphagnum platyphyllum in one of its flush complexes, but otherwise these outlying moors are of little bryological interest.  This is probably because of a combination of climate and a regular management by burning; the burning does appear to favour Bryum bornholmense however.

Although many peatlands have suffered from drainage, aforestation and neglect, Carmarthenshire retains a good number, especially on the coalfield.  The specialist liverworts Odontoschisma fluitans, Kurzia pauciflora, Mylia anomala and Odontoschisma sphagni are present at many sites and are abundant at Cors Goch Llanllwch (SN31) and in some of the bogs near Carmel (SN51).  More notable species are surprisingly sparse on the county’s peatlands: Pallavicinia lyellii has been recorded from bogs at Llanpumsaint (SN42), Cors Goch Llanllwch (SN31), Glyn Bog (SN31) and Llyn Llech Owain (SN51), whilst Sphagnum magellanicum is present at Pyllau cochion (SN52), Mynydd Pencarreg (SN54) and Mawnbwll Du-mawr (SN82).

Almost all of the south Wales reservoirs were surveyed in the early 21st century and populations of Riccia huebeneriana were noted at several, mostly in Breconshire.  This species occurs at both Cwm Lliedi Reservoir (SN50), near Llanelli, and Usk Reservoir (SN82), in the north-east of the county.  Cwm Lliedi Reservoir is also significant for supporting an enormous population of Physcomitrium sphaericum, known from just one other Welsh site, whilst Fossombronia foveolata is present at Usk Reservoir.  Riccia huebeneriana was collected by Knight at Talley Lakes (SN63) but water levels there have always been too high in recent years to ascertain whether it persists.  The seasonal lake at Pant-y-llyn (SN61) supports one of only two known UK populations of Ephemerum hibernicum and the only county population of Fontinalis antipyretica ‘var. gigantea’ and the only inland population of Riccia cavernosaAphanoregma patens and Ephemerum stoloniferum (formerly E. serratum) are also present.  Several ox-bow lakes by the Afon Tywi support Riccia fluitans.

The bryophyte flora of Carmarthenshire’s rivers varies considerably according to their size, pH and the nature of the rock that they flow over.  With the exception of Dendrocryphaea lamyana, only known in Wales on the Teifi, one of its tributaries and one site on the Tywi at Nantgaredig (SN42), Myrinia pulvinata is the rarest riverine moss in Carmarthenshire with its sole locus at Bishops Pond (SN42).  Two of the few British records of Fissidens monguillonii come from the Tywi.  The rocky upper reaches of that river have a quite different character to its middle and lower reaches and support a different flora, including Racomitrium macounii subsp. alpinum, mentioned above under Dinas and Rhuddallt.  Strikingly different is the Gwendraeth Fach (SN40), where the lowland species Dialytrichia mucronata and Fissidens crassipes are found.

The small, north-facing crag of Craig y’ Sawrwg (SN71) above the upper Sawdde Fechan supports many of the bryophytes that make Bannau Sir Gaer, four kilometres to the east-northeast, such a significant site.  These include Jungermannia borealis, Andreaea alpina, Ditrichum zonatum var. zonatum, Encalypta ciliata and Schistidium strictum as well as Plagiothecium denticulatum var. obtusifolium at its only known Carmarthenshire site; furthermore, Plagiopus oederianus is more abundant here than anywhere else in the county.  Most of these species are at or near their southern British limit.  The series of crags by the Afon Clydach (SN71) has been known to hold Bartramia halleriana and P. oederianus since Knight’s time and also supports Scapania aequiloba and plenty of Mnium marginatum and Orthothecium intricatumCraig Ddu, Gwenffrwd is the only extensive unwooded crag in the Carmarthenshire part of SN74 and is notable for supporting one of just two colonies of Cololejeunea calcarea recorded in the vice-county as well as one of only two known colonies of Blindiadelphus recurvatus in the county’s north-east.

Craig y Sawrwg is an isolated sandstone outcrop supporting a suite of uncommon montane bryophytes

As well as Foel Fawr and Carreg Cennen, mentioned above, there are exposures of Carboniferous Limestone elsewhere on Mynydd Du.  Pâl y Cwrt (SN61) has a number of unquarried faces and consequently Seligeria acutifolia is frequent; it also boasts the county’s only Funaria muhlenbergii.  The high altitude limestone pavement of Carreg yr Ogof (SN72) is one of a handful of upland sites in south Wales that support Bryum mildeanum; it also supports the gemmiferous form of Bryum pallens and a little S. acutifolia.  Further interest is provided by various lowland taxa that reach their local altitudinal maximum there. Mnium thomsonii was found new to south Wales on Banc Wernwgan (SN61) in 2011.

Dryslwyn Castle (SN52) is situated on the most exposed of four outcrops of Ordovician Limestone in the Tywi valley, and has a subtly different bryophyte flora from the Carboniferous areas, mostly because of its parched south-facing slopes.  It is one of the most important sites in the vice-county for Mediterranean-Atlantic bryophytes, holding five species, including Cololejeunea rossettiana, Fissidens curvatus and Microbryum rectum, otherwise unknown in Carmarthenshire.  Cephaloziella stellulifera, Bryum donianum, Gymnostomum viridulum, Tortula caucasica (T. modica) and T. lindbergii (T. lanceola) are among the other notable species at this very unusual site. Orthotrichum cambense has its only known site in the world in the carpark adjacent to Dryslwyn Castle.

The county’s gorges are, like crags, often foci of notable bryophytes, but their inaccessibility makes documentation of these difficult.  Hygrobiella laxifolia is locally abundant in Cwm Twrch (SN71), which forms the border with Breconshire on Mynydd Du, together with Jungermannia hyalina, J. obovata and J. paroica.  The Sawdde Gorge (SN72), which cuts through Silurian sandstone near Llangadog, has locally abundant Grimmia hartmanii on its walls, small colonies of Cololejeunea calcarea, Plagiopus oederianus and Rhytidiadelphus subpinnatus, and Fissidens rufulus on semi-submerged rocks, whilst Knight found Didymodon spadiceus there.  Further north, the gorge of the Afon Gwenffrwd holds the largest colony of Bartramia halleriana in the county, as well as Heterocladium wulfsbergii, Rhynchostegium lusitanicum and relatively convincing Fissidens taxifolius var. pallidicaulisJubula hutchinsae, once thought to be rare in south Wales, has been found in several gorges, notably in Llanelli Borough.  Small crags by the Afon Gwydderig (SN83) support small populations of B. halleriana and Plagiochila spinulosaFissidens rufulus grows on rocks in the river and there are old records of Cephaloziella stellulifera and C. turneri.

The Sawdde Gorge has abundant riverside rocks, supporting a strong population of Grimmia hartmannii

Carmarthenshire’s only open, unwooded igneous rocks are in the disused quarry at Llangynog (SN31) and consequently it is of considerable bryological interest.  Grimmia is especially diverse here, with G. decipiens, G. donniana, G. laevigata, G. longirostris and G. ovalis in addition to the common G. pulvinata and G. trichophylla; Hedwigia stellata is another notable saxicolous moss present.  Fossombronia incurva grows here on damp gravel, as it does in several other quarries in the county, and Aloina ambigua occurs at its only county site.  Iet y Bwlch Quarry (SN12), in the far west of Carmarthenshire, supports a large colony of Ephemerum sessile as well as smaller numbers of E. serratum.

Nant y Bai lead mine (SN74) is one of only two of the widely scattered mines in the county’s north-east that is known to be of bryological interest and survey work in the 1990s (Martin et al., 1994) covered these sites fairly thoroughly.  Ditrichum plumbicola is the primary interest at Nant y Bai.  It grows on highly toxic, frost-heaved soil of a kind that is absent from most of Carmarthenshire’s other mines. One area of ‘slime pits’ also holds Scopelophila cataractaeTetraplodon mnioides, which grows on dung at Nant y Bai and is known from just one other site, is also of note, as is an introduced colony of Petalophyllum ralfsiiDitrichum plumbicola also occurs at the smaller Nant y Mwyn mine (SN74) near Rhandirmwyn, where Weissia controversa var. densifolia is also present.

There is similar coastal habitat to that at Laugharne on the other side of the Tâf estuary at Llansteffan (SN31).  This is slightly less diverse, lacking coastal Frullania spp., Coscinodon cribrosus and Grimmia lisae, but does support Hennediella heimei, Schistidium maritimum and Tortula viridifolia.  Knight recorded Targionia hypophylla at Llansteffan Castle but it has not been refound.  Of particular note are the strong population of Gymnostomum viridulum at Craig Ddu and the only known Carmarthenshire colony of Microbryum starckeanum at Llansteffan.  Further east, Knight found T. viridifolia near Kidwelly, but otherwise the coast in that area does not appear to have significant bryophyte interest.  Hennediella heimei and Tortula caucasica (T. modica) are typical of the upper reaches of saltmarshes in the Llanelli area.

Coniferisation has damaged the dunes at Pembrey to such an extent that little interesting bryophyte habitat remains – remnant slacks support Drepanocladus aduncus and dried-up pools hold Riccia cavernosa.  Better habitat remains north of the forest at Tywyn Burrows (SN30), where Amblyodon dealbatus and Kandaea elodes grow in slacks together with marsh helleborine and variegated horsetail and Amblystegium serpens var. salinum creeps across damp sand. The dune-saltmarsh transition north of Tywyn Burrows provides suitable conditions for Bryum marratii, and this rare species also grows in a similar locus just north of Ferryside (SN31).  Although smaller remnant dune systems at Llansteffan (SN31), Burry Port (SN40) and Llanelli (SS49) support various notable vascular plants, they are of little bryological significance.  Bryum algovicum var. rutheanum and Rhynchostegium megapolitanum are the only species of any note recorded at these sites.

The Mosses and Liverworts of Carmarthenshire

by Sam Bosanquet, Jonathan Graham & Graham Motley

Based on 13 years of recording by three members of the Society, this is the first published book on the mosses and liverworts of Carmarthenshire. Over 600 species, sub-species and varieties of mosses, liverworts and hornworts have been recorded from the county in habitats ranging from coastal dunes to montane crags. The distribution of each species is described, with distribution maps presented for those occurring in five or more tetrads. Accompanying notes include information on habitat, ecology, fertility and significance in a local, Welsh or British context. The Flora is 240 pages long and is illustrated with 32 photographs of key local bryophyte sites and some of our most distinctive species.

Introductory chapters cover:

  • the physical background of Carmarthenshire, including its geology, soils and climate
  • broad bryophyte habitats in the county and the common species they support
  • the history of bryophyte recording in the county from the early 20th century explorations of H.H. Knight to the intensive tetrad recording of recent years
  • a comparison between the Carmarthenshire bryophyte flora as represented by the BBS bryophyte Atlas and by the current Flora
  • comparison with the bryophyte floras of the adjacent vice-counties of Pembrokeshire, Cardiganshire, Breconshire and Glamorgan
  • examination of the biogeographical elements represented in the bryophyte flora
  • details of the key sites for bryophytes in the county and the representation of notable bryophyte species on Sites of Special Scientific Interest
  • an account of the changing bryophyte flora of the county, with reference both to declining species and increasing species

Available from Sam Bosanquet (, Dingestow Court, Monmouth, Monmouthshire NP25 4DY

Usual price £20.00 (+ £4.64 p&p); special reduced price for BBS members £15.00 (+ £4.64 p&p)

ISBN 0-9552022-0-5 / 978-0-9552022-0-9

Local floras

Bosanquet, S., Graham, J. & Motley, G. 2006. The Mosses and Liverworts of Carmarthenshire (see details above)

Wade, A.E. 1948. The bryophytes of Carmarthenshire. I. Hepaticae. Transactions of the British Bryological Society1: 65-69.

Wade AE. 1949. The bryophytes of Carmarthenshire. II. Musci. Transactions of the British Bryological Society1: 172-180.