Gweunydd Penstrowed

Site of Special Scientific Interest · 52.5059, -3.3756

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Powys County

Description

Description The site consists of two discrete steeply sloping fields on either side of a dingle. Their aspects are predominantly north-facing and south-facing respectively. Much of the site is poorly drained, with wet flushes occurring particularly in the north-facing field, but steep banks provide drier habitat in places. The site is used as rough pasture for cattle. The sward is of bents and fescues (Agrostis/Festuca), but with a range of other grass species including cock’s-foot Dactylis glomerata, crested dog's-tail Cynosurus cristatus and wavy hair-grass Deschampsia flexuosa. Quaking-grass Briza media is particularly well represented in the southern (north-facing) field. The plant communities represented here differ according to variations in drainage and in the base-status of the soil. They vary from the more acid types of sward, typified by tormentil/mat-grass Potentilla erecta/Nardus stricta with eyebright Euphrasia officinalis or devil's-bit scabious Succisa pratensis, to more neutral components typified by zones dominated by common knapweed Centaurea nigra in which both primrose Primula vulgaris and cowslip P. veris are well represented. Rush-dominated flushes with tall-herbs and sedges add further diversity. Orchid species recorded from the site include the uncommon lesser butterfly-orchid Platanthera bifolia. Butterfly species recorded from the site include the small skipper Thymelicus sylvestris and common blue Polyommatus icarus.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
common blue Polyommatus icarus LC butterfly lycaenidae
small skipper Thymelicus sylvestris LC butterfly hesperiidae
quaking grass Briza media VU grass poaceae
crested dog's tail Cynosurus cristatus LC grass poaceae
cock's foot Dactylis glomerata LC grass poaceae
wavy hair grass Deschampsia flexuosa Not listed in GB list grass poaceae
mat grass Nardus stricta LC grass poaceae
black knapweed Centaurea nigra LC herb asteraceae
English sticky eyebright Euphrasia officinalis LC herb orobanchaceae
lesser butterfly orchid Platanthera bifolia VU herb orchidaceae
tormentil Potentilla erecta LC herb rosaceae
primrose Primula vulgaris LC herb primulaceae
devils-bit scabious Succisa pratensis VU herb caprifoliaceae

Insects to look out for

These moths, butterflies and beetles 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
Black-veined moth
Siona lineata
Critically Endangered Centaurea nigra
Duke of Burgundy
Hamearis lucina
Endangered Primula vulgaris
Marsh fritillary
Euphydryas aurinia
Vulnerable Succisa pratensis
Satyr pug
Eupithecia satyrata
Vulnerable Centaurea spp.
Grizzled skipper
Pyrgus malvae
Vulnerable Potentilla erecta
Hedge rustic
Tholera cespitis
Vulnerable Nardus stricta
Large nutmeg
Apamea anceps
Near Threatened Dactylis glomerata
Small heath
Coenonympha pamphilus
Near Threatened Cynosurus cristatus, Nardus stricta
Small mountain ringlet
Erebia epiphron
Near Threatened Nardus stricta
Grey pug
Eupithecia subfuscata
Near Threatened Centaurea spp.
Scarce forester
Jordanita globulariae
Near Threatened Centaurea nigra
Wall
Lasiommata megera
Near Threatened Dactylis glomerata
Rosy minor
Litoligia literosa
Near Threatened Dactylis glomerata

Host-plant 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; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.