Cassop Vale is a

Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland is a conservation designation denoting a protected area in the United Kingdom and Isle of ...

in the Durham City district of

County Durham County Durham ( ), officially simply Durham,UK General Acts 1997 c. 23Lieutenancies Act 1997 Schedule 1(3). From legislation.gov.uk, retrieved 6 April 2022. is a ceremonial county in North East England.North East Assembly �About North East E ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. It lies between the villages of

Bowburn Bowburn is a village in County Durham, England. It is situated about to the south-east of Durham, on the A177, between Coxhoe to the south-east, and High Shincliffe to the north-west. It is part of the Cassop-cum-Quarrington parish. History ...

and

Cassop Cassop (formerly New Cassop) is a village in County Durham, in England. It has a population of about 500 and is located near the city of Durham. A former mining village, mining is no longer the main occupation of Cassop's inhabitants due to exte ...

, 7 km south-east of the centre of Durham.. The site is important as one of the larger areas of grassland developed on magnesium

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

. This rock has a restricted distribution in England and grassland associated with it is confined almost entirely to south-east

Tyneside Tyneside is a built-up area across the banks of the River Tyne in northern England. Residents of the area are commonly referred to as Geordies. The whole area is surrounded by the North East Green Belt. The population of Tyneside as published i ...

and County Durham, usually in small, scattered patches that are threatened by quarrying and modern agricultural practices. Habitats at Cassop Vale include grassland, scrub, woodland and wetland, the last fed by spring-lines. The area also includes recolonised open quarries and mine spoil-heaps, which add to the floral diversity. The main grass species on the magnesian limestone is blue moor-grass ''

Sesleria albicans ''Sesleria albicans'' is a species of perennial grass in the family Poaceae which can be found throughout Europe. Description The species is perennial and caespitose with erect and slender culms that are long. It have a ligule that goes arou ...

'' amongst which grow fragrant orchid ''

Gymnadenia conopsea ''Gymnadenia conopsea'', commonly known as the fragrant orchid or chalk fragrant orchid, is a herbaceous plant of the family Orchidaceae native to northern Europe. Etymology The name of the genus ''Gymnadenia'' is formed from Greek words (', ...

'', cowslip, ''

Primula veris ''Primula veris'', the cowslip, common cowslip, or cowslip primrose ( syn. ''Primula officinalis'' ), is a herbaceous perennial flowering plant in the primrose family Primulaceae. The species is native throughout most of temperate Europe and w ...

'', rock rose ''

Helianthemum nummularium ''Helianthemum nummularium'' (known as common rock-rose) is a species of rock-rose (Cistaceae), native to most of Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical si ...

'', and quaking grass, ''

Briza media ''Briza media'' is a perennial grass in the family Poaceae and is a species of the genus ''Briza''. Common name includes quaking-grass, common quaking grass, cow-quake, didder, dithering-grass, dodder-grass, doddering dillies, doddle-grass, eart ...

''. Several rare and local species are present, including globeflower, ''

Trollius europaeus ''Trollius europaeus'', the globeflower, is a perennial flowering plant of the family Ranunculaceae. The plant is native to Europe and Western Asia and is a protected species in Russia and Bulgaria. In Udmurtia, this plant is one of the nation ...

'', birds's-eye primrose, ''

Primula farinosa ''Primula farinosa'', the bird's-eye primrose, is a small perennial plant in the family Primulaceae, native to Northern Europe and northern Asia, and (rarely) farther south at high altitudes in the mountains of southern Europe. This primrose th ...

'', lesser club-moss, ''

Selaginella selaginoides ''Selaginella selaginoides'' is a non-flowering plant of the spikemoss genus ''Selaginella'' with a wide distribution around the Northern Hemisphere. It resembles a moss in appearance but is a vascular plant belonging to the division (botany), di ...

'', and moonwort, ''

Botrychium lunaria ''Botrychium lunaria'' is a species of fern in the family Ophioglossaceae known by the common name moonwort or common moonwort. It is the most widely distributed moonwort, growing throughout the Northern Hemisphere across Eurasia and from Alaska ...

''. Elsewhere there is neutral grassland with

red fescue ''Festuca rubra'' is a species of grass known by the common name red fescue or creeping red fescue. It is widespread across much of the Northern Hemisphere and can tolerate many habitats and climates. It is best adapted to well-drained soils in c ...

and such herbs as cat’s-ear, earthnut and

knapweed ''Centaurea'' () is a genus of over 700 species of herbaceous thistle-like flowering plants in the family Asteraceae. Members of the genus are found only north of the equator, mostly in the Eastern Hemisphere; the Middle East and surrounding reg ...

. The scrub is dominated by

hawthorn Hawthorn or Hawthorns may refer to: Plants * '' Crataegus'' (hawthorn), a large genus of shrubs and trees in the family Rosaceae * ''Rhaphiolepis'' (hawthorn), a genus of about 15 species of evergreen shrubs and small trees in the family Rosace ...

gorse ''Ulex'' (commonly known as gorse, furze, or whin) is a genus of flowering plants in the family Fabaceae. The genus comprises about 20 species of thorny evergreen shrubs in the subfamily Faboideae of the pea family Fabaceae. The species are n ...

and

hazel The hazel (''Corylus'') is a genus of deciduous trees and large shrubs native to the temperate Northern Hemisphere. The genus is usually placed in the birch family Betulaceae,Germplasmgobills Information Network''Corylus''Rushforth, K. (1999). ...

and on the basic soils grow woodruff,

dog's mercury ''Mercurialis perennis'', commonly known as dog's mercury, is a poisonous woodland plant found in much of Europe as well as in Algeria, Iran, Turkey, and the Caucasus, but almost absent from Ireland, Orkney and Shetland.sanicle ''Sanicula'' is a genus of plants in Family (biology), family Apiaceae (or Umbelliferae), the same family to which the carrot and parsnip belong. This genus has about 45 species worldwide, with at least 22 in North America.Focus on Rarities (fro ...

. The small flushes on the springline are dominated by rushes and sedges, but are also home to

marsh valerian ''Valeriana dioica'', the marsh valerian, is a species of flowering plant in the genus ''Valeriana ''Valeriana'' is a genus of flowering plants in the family Caprifoliaceae, members of which may by commonly known as valerians. It contains many ...

marsh ragwort ''Jacobaea aquatica'' or ''Senecio aquaticus'', the water ragwort or marsh ragwort, is a plant of the family Asteraceae. It is a perennial or biennial plant: young plants form a rosette near the ground, eventually producing a taller flowering sh ...

ragged robin ''Silene flos-cuculi'' (syn. ''Lychnis flos-cuculi''), commonly called ragged-robin, is a perennial herbaceous plant in the family Caryophyllaceae. This species is native to Europe and Asia, where it is found along roads and in wet meadows and p ...

and northern marsh-orchid. The wetlands are fringed by

common spike-rush ''Eleocharis palustris'', the common spike-rush, creeping spike-rush or marsh spike-rush, is a species of mat-forming perennial flowering plants in the sedge family Cyperaceae. It grows in wetlands in Europe, North Africa, northern and central A ...

soft rush ''Juncus effusus'', with the common names common rush or soft rush, is a perennial herbaceous flowering plant species in the rush family Juncaceae. In North America, the common name soft rush also refers to '' Juncus interior''. Distribution '' ...

and greater willow-herb. The site also supports a diverse invertebrate fauna that includes populations of the Durham argus butterfly, '' Aricia artaxerxes salmacis'', and the least minor moth ''

Photedes captiuncula ''Photedes captiuncula'', the least minor, is a moth of the family Noctuidae. It is found throughout Europe, in Turkey, Armenia, Russia and much of temperate Asia (western Siberia, Altai mountains, Central Asia and Amur). Technical description an ...

''.

References

{{SSSIs County Durham Sites of Special Scientific Interest in County Durham