Rhos Glyn-yr-helyg

Site of Special Scientific Interest · 52.1403, -4.1969

Open in the interactive map →

Also within

Dyfed County

Habitats

Purple moor grass and rush pasture

Geology & landscape

Landscape processes: Glacial

Description

Description An excellent and extensive example of unimproved sedge-rich pasture, situated near the Afon Grannell. This type of wet grassland (known locally as ‘rhos’) is well represented in Ceredigion, and evidently it was widespread in the past. Dry banks, neglected ditches and flushes add diversity to the site and enrich the flora. In the main, the sward consists of a grass-sedge community containing sweet vernal-grass Anthoxanthum odoratum, Yorkshire-fog Holcus lanatus and purple moor-grass Molinia caerulea as the dominant grasses, together with a number of sedge species. The forbs include heath spotted-orchid Dactylorhiza maculata subsp. ericetorum, whorled caraway Carum verticillatum, dyer’s greenweed Genista tinctoria, ragged-robin Lychnis flos-cuculi, lousewort Pedicularis sylvatica and devil’s-bit scabious Succisa pratensis. The site also has physiographic interest, being situated in an area where glacial features known as pingos have been recorded. Within the site itself, there are two actively growing basin mires situated in what are believed to be pingos. The mires, which have a rich flora, greatly add to the overall interest of this remarkable site. Remarks: Owned by the West Wales Naturalists’ Trust and managed as a nature reserve.

Species mentioned

English name
search for this in other sites		 Latin name
search with Google		 IUCN / Red List Type Family
sweet vernal grass Anthoxanthum odoratum LC grass poaceae
Yorkshire fog Holcus lanatus LC grass poaceae
purple moor grass Molinia caerulea LC grass poaceae
whorled caraway Carum verticillatum Not listed in GB list herb apiaceae
heath spotted orchid Dactylorhiza maculata subsp. ericetorum Not listed in GB list herb orchidaceae
dyer's greenweed Genista tinctoria LC herb fabaceae
lousewort Pedicularis sylvatica NT herb orobanchaceae
devils-bit scabious Succisa pratensis VU herb caprifoliaceae

Plant communities

M23 — Coastal floodplain grazing marsh, Purple moor grass and rush pasture, Upland rush pasture

Juncus effusus/acutiflorus-Galium palustre rush-pasture

Matches 5 species from the description above: Anthoxanthum odoratum, Carum verticillatum, Holcus lanatus, Molinia caerulea, Succisa pratensis

Carex demissa, Carex echinata, Carex nigra, Carex panicea, Juncus acutiflorus, Juncus articulatus, Juncus bulbosus, Juncus conglomeratus, Juncus effusus, Luzula campestris, Luzula multiflora, Aulacomnium palustre, Brachythecium rivulare, Brachythecium rutabulum, Calliergon cordifolium, Calliergonell cuspidatum, Kindbergia praelonga, Rhytidiadelphus squarrosus, Polytrichum commune, Calypogeia fissa, Lophocolea bidentata, Pellia epiphylla, Angelica sylvestris, Carum verticillatum, Hydrocotyle vulgaris, Achillea ptarmica, Caltha palustris, Cirsium palustre, Senecio aquaticus, Taraxacum officianalis, Myosotis laxa, Myosotis secunda, Cardamine flexuosa, Cardamine pratensis, Succisa pratensis, Valeriana officinalis, Cerastium fontanum, Silene flos-cuculi, Stellaria alsine, Stellaria graminea, Equisetum fluviatile, Equisetum palustre, Lathyrus pratensis, Lotus pedunculatus, Trifolium repens, Iris pseudacorus, Mentha aquatica, Scutellaria minor, Lythrum salicaria, Narthecium ossifragum, Epilobium obscurum, Epilobium palustre, Dactylorhiza maculata, Plantago lanceolata, Veronica scutellata, Polygonum hydropiper, Rumex acetosa, Primula vulgaris, Ranunculus acris, Ranunculus flammula, Ranunculus repens, Comarum palustre, Filipendula ulmaria, Potentilla anserina, Potentilla erecta, Galium palustre, Viola palustris, Agrostis canina, Agrostis capillaris, Agrostis stolonifera, Anthoxanthum odoratum, Cynosurus cristatus, Deschampsia cespitosa, Festuca rubra, Glyceria fluitans, Holcus lanatus, Molinia caerulea, Poa pratensis, Poa trivialis, Dryopteris expansa, Athyrium filix-femina

M24 — Coastal floodplain grazing marsh, Lowland fen, Purple moor grass and rush pasture

Molinia caerulea-Cirsium dissectum fen-meadow

Matches 5 species from the description above: Anthoxanthum odoratum, Holcus lanatus, Molinia caerulea, Pedicularis sylvatica, Succisa pratensis

Salix cinerea, Salix repens, Alnus glutinosa, Calluna vulgaris, Erica tetralix, Carex hostiana, Carex nigra, Carex panicea, Carex pulicaris, Cladium mariscus, Eriophorum angustifolium, Schoenus nigricans, Juncus acutiflorus, Juncus articulatus, Juncus conglomeratus, Juncus effusus, Juncus subnodulosus, Luzula multiflora, Aulacomnium palustre, Brachythecium rutabulum, Calliergonell cuspidatum, Hypnum cupressiforme, Kindbergia praelonga, Pseudoscleropodium purum, Thuidium tamariscinum, Sphagnum auriculatum, Sphagnum subnitens, Angelica sylvestris, Hydrocotyle vulgaris, Achillea ptarmica, Centaurea nigra, Cirsium arvense, Cirsium dissectum, Cirsium palustre, Eupatorium cannabinum, Leontodon saxatilis, Pulicaria dysenterica, Senecio aquaticus, Serratula tinctoria, Cardamine pratensis, Succisa pratensis, Valeriana dioica, Cerastium fontanum, Silene flos-cuculi, Drosera rotundifolia, Equisetum palustre, Lathyrus pratensis, Lotus pedunculatus, Trifolium pratense, Vicia cracca, Hypericum tetrapterum, Hypericum undulatum, Mentha aquatica, Scutellaria minor, Linum catharticum, Lythrum salicaria, Narthecium ossifragum, Dactylorhiza fuchsii, Dactylorhiza incarnata, Dactylorhiza maculata, Epipactis palustris, Gymnadenia conopsea, Pedicularis sylvatica, Plantago lanceolata, Polygala vulgaris, Rumex acetosa, Anagallis tenella, Primula vulgaris, Ranunculus acris, Ranunculus flammula, Filipendula ulmaria, Potentilla anserina, Potentilla erecta, Potentilla reptans, Rubus fruticosus agg., Galium palustre, Galium uliginosum, Galium verum, Viola palustris, Agrostis canina, Agrostis stolonifera, Anthoxanthum odoratum, Briza media, Danthonia decumbens, Deschampsia cespitosa, Festuca rubra, Holcus lanatus, Molinia caerulea, Phragmites australis

M25 — Blanket bog, Coastal floodplain grazing marsh, Lowland fen, Purple moor grass and rush pasture, Upland acid grassland

Molinia caerulea-Potentilla erecta mire

Matches 5 species from the description above: Anthoxanthum odoratum, Carum verticillatum, Holcus lanatus, Molinia caerulea, Succisa pratensis

Salix cinerea, Calluna vulgaris, Erica tetralix, Myrica gale, Vaccinium oxycoccos, Ulex europaeus, Ulex gallii, Carex echinata, Carex flacca, Carex nigra, Carex panicea, Eriophorum angustifolium, Schoenus nigricans, Juncus acutiflorus, Juncus articulatus, Juncus effusus, Juncus subnodulosus, Luzula campestris, Luzula multiflora, Aulacomnium palustre, Pohlia nutans, Calliergon giganteum, Calliergonell cuspidatum, Hypnum jutlandicum, Kindbergia praelonga, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Polytrichum commune, Sphagnum auriculatum, Sphagnum capillifolium, Sphagnum fallax, Sphagnum palustre, Sphagnum papillosum, Sphagnum subnitens, Calypogeia fissa, Cephalozia bicuspidata, Lophocolea bidentata, Lophozia ventricosa, Angelica sylvestris, Carum verticillatum, Hydrocotyle vulgaris, Achillea ptarmica, Centaurea nigra, Cirsium palustre, Eupatorium cannabinum, Pulicaria dysenterica, Serratula tinctoria, Cardamine pratensis, Lobelia urens, Succisa pratensis, Valeriana officinalis, Equisetum palustre, Lotus pedunculatus, Hypericum pulchrum, Hypericum tetrapterum, Mentha aquatica, Scutellaria minor, Menyanthes trifoliata, Narthecium ossifragum, Epilobium palustre, Dactylorhiza maculata, Rumex acetosa, Ranunculus acris, Ranunculus flammula, Filipendula ulmaria, Potentilla erecta, Rubus fruticosus agg., Galium palustre, Viola palustris, Agrostis canina, Agrostis capillaris, Agrostis curtisii, Agrostis stolonifera, Anthoxanthum odoratum, Danthonia decumbens, Deschampsia cespitosa, Festuca ovina, Festuca rubra, Holcus lanatus, Molinia caerulea, Nardus stricta, Phragmites australis, Dryopteris carthusiana, Osmunda regalis

M22 — Coastal floodplain grazing marsh, Lowland fen, Purple moor grass and rush pasture

Juncus subnodulosus-Cirsium palustre fen-meadow

Matches 4 species from the description above: Anthoxanthum odoratum, Holcus lanatus, Molinia caerulea, Succisa pratensis

Salix cinerea, Solanum dulcamara, Carex acutiformis, Carex disticha, Carex elata, Carex flacca, Carex hirta, Carex lepidocarpa, Carex nigra, Carex panicea, Carex rostrata, Cladium mariscus, Eriophorum angustifolium, Eleocharis palustris, Eleocharis uniglumis, Juncus articulatus, Juncus effusus, Juncus inflexus, Juncus subnodulosus, Luzula multiflora, Plagiomnium affine, Plagiomnium rostratum, Plagiomnium undulatum, Rhizomnium punctatum, Brachythecium rutabulum, Calliergonell cuspidatum, Cratoneuron filicinum, Pseudoscleropodium purum, Lophocolea bidentata, Angelica sylvestris, Berula erecta, Oenanthe lachenalii, Thyselium palustre, Hydrocotyle vulgaris, Achillea ptarmica, Caltha palustris, Centaurea nigra, Cirsium arvense, Cirsium dissectum, Cirsium palustre, Eupatorium cannabinum, Pulicaria dysenterica, Myosotis laxa, Myosotis scorpioides, Cardamine pratensis, Succisa pratensis, Valeriana dioica, Valeriana officinalis, Cerastium fontanum, Silene flos-cuculi, Stellaria palustris, Calystegia sepium, Equisetum fluviatile, Equisetum palustre, Lathyrus pratensis, Lotus pedunculatus, Trifolium pratense, Trifolium repens, Vicia cracca, Hypericum tetrapterum, Iris pseudacorus, Triglochin palustre, Ajuga reptans, Lycopus europaeus, Mentha aquatica, Lemna minor, Lythrum salicaria, Menyanthes trifoliata, Epilobium hirsutum, Epilobium palustre, Epilobium parviflorum, Dactylorhiza fuchsii, Dactylorhiza incarnata, Dactylorhiza praetermissa, Epipactis palustris, Pedicularis palustris, Rhinanthus minor, Plantago lanceolata, Veronica beccabunga, Polygonum amphibium, Rumex acetosa, Rumex conglomeratus, Rumex sanguineus, Lysimachia vulgaris, Primula vulgaris, Ranunculus acris, Ranunculus flammula, Ranunculus repens, Thalictrum flavum, Comarum palustre, Filipendula ulmaria, Potentilla anserina, Potentilla erecta, Potentilla reptans, Galium palustre, Galium uliginosum, Scrophularia auriculata, Scutellaria galericulata, Agrostis stolonifera, Anthoxanthum odoratum, Arrhenatherum elatius, Briza media, Calamagrostis canescens, Cynosurus cristatus, Deschampsia cespitosa, Festuca rubra, Holcus lanatus, Molinia caerulea, Phalaris arundinacea, Phleum pratense, Phragmites australis, Poa trivialis, Schedonorus arundinaceus, Ophioglossum vulgatum, Thelypteris palustris

M26 — Limestone pavement, Purple moor grass and rush pasture

Molinia caerulea-Crepis paludosa mire

Matches 4 species from the description above: Anthoxanthum odoratum, Holcus lanatus, Molinia caerulea, Succisa pratensis

Carex appropinquata, Carex disticha, Carex echinata, Carex flacca, Carex hostiana, Carex nigra, Carex panicea, Carex pulicaris, Juncus acutiflorus, Juncus articulatus, Juncus conglomeratus, Aulacomnium palustre, Plagiomnium undulatum, Calliergonell cuspidatum, Campylium elodes, Climacium dendroides, Ctenidium molluscum, Hylocomium splendens, Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Thuidium tamariscinum, Lophocolea bidentata, Plagiochila asplenioides, Angelica sylvestris, Caltha palustris, Centaurea nigra, Cirsium palustre, Crepis paludosa, Leontodon hispidus, Serratula tinctoria, Succisa pratensis, Valeriana dioica, Silene flos-cuculi, Equisetum fluviatile, Equisetum palustre, Lathyrus pratensis, Trifolium repens, Menyanthes trifoliata, Rhinanthus minor, Plantago lanceolata, Rumex acetosa, Primula farinosa, Primula vulgaris, Anemone nemorosa, Ranunculus acris, Ranunculus auricomus, Trollius europaeus, Comarum palustre, Filipendula ulmaria, Geum rivale, Potentilla erecta, Sanguisorba officinalis, Galium palustre, Galium uliginosum, Agrostis stolonifera, Anthoxanthum odoratum, Briza media, Deschampsia cespitosa, Festuca ovina, Festuca rubra, Holcus lanatus, Molinia caerulea, Phragmites australis

Insects to look out for

These moths and butterflies are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

SpeciesStatusVia host-plant
Chequered skipper
Carterocephalus palaemon		 Endangered Molinia caerulea
Large heath
Coenonympha tullia		 Vulnerable Molinia caerulea
Marsh fritillary
Euphydryas aurinia		 Vulnerable Succisa pratensis
Lead belle
Scotopteryx mucronata		 Vulnerable Genista tinctoria
The anomalous
Stilbia anomala		 Vulnerable Molinia caerulea
Silver barred
Deltote bankiana		 Near Threatened Molinia caerulea
Wall
Lasiommata megera		 Near Threatened Holcus lanatus

Hostplant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation (Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.