Purn Hill () is a 6.1

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...

biological 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 ...

near the village of

Bleadon Bleadon is a village and civil parish in Somerset, England. It is about south of Weston-super-Mare and, according to the 2011 census, has a population of 1,079. History Bleadon was listed in the Domesday Book of 1086 as ''Bledone'', meaning 'c ...

Somerset ( en, All The People of Somerset) , locator_map = , coordinates = , region = South West England , established_date = Ancient , established_by = , preceded_by = , origin = , lord_lieutenant_office =Lord Lieutenant of Somerset , lord_ ...

, notified in 1990. The site is a small promontory of

Carboniferous Limestone Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian epoch (geology), Epoch of the Carboniferous period (geology), Period. T ...

projecting southward from the main

Mendip Mendip may refer to: *Mendip District, a local government district of Somerset, England * Mendip Hills, a group of hills in Somerset, England ** Mendip Way, a footpath across the Mendip Hills **Mendip TV Mast, a transmitter in the Mendips area *For ...

ridge. The SSSI citation sheet describes the site as having an "exceptionally diverse unimproved calcareous grassland flora". The richest grassland communities are situated on the thin and stony soils of the steeper west-facing flanks of the hill. Over 200 species occur in the sward, including Salad Burnet (''

Sanguisorba minor ''Sanguisorba minor'', the salad burnet, garden burnet, small burnet, burnet (also used for ''Sanguisorba'' generally), pimpernelle, Toper's plant, and burnet-bloodwort, is an edible perennial herbaceous plant in the family Rosaceae. It has fe ...

''), Dropwort (''

Filipendula vulgaris ''Filipendula vulgaris'', commonly known as dropwort or fern-leaf dropwort, is a perennial herbaceous plant in the family Rosaceae, closely related to meadowsweet (''Filipendula ulmaria''). It is found in dry pastures across much of Europe an ...

''), Fairy Flax (''

Linum catharticum ''Linum catharticum'', also known as purging flax, or fairy flax, is an herbaceous flowering plant in the family Linaceae, native to Great Britain, Iceland, central Europe and Western Asia. It is an annual plant and blooms in July and August. It ...

''), Kidney Vetch (''

Anthyllis vulneraria ''Anthyllis vulneraria'', the common kidneyvetch, kidney vetch or woundwort is a medicinal plant native to Europe. The name ''vulneraria'' means "wound healer". Description ''Anthyllis vulneraria'' reaches of height. The stem is simple or more ...

'') and Dwarf Thistle (''

Cirsium acaule ''Cirsium acaule'' or ''acaulon'' has the English name dwarf thistle or stemless thistle. It is widespread across much of Europe.

''). The rare plants are mainly associated with the small exposures of

dolomitic Dolomite () is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite. An alternative name sometimes used for the dolomiti ...

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 ...

in the southern part of the site. Purn Hill is one of only five British sites for the nationally rare coastal limestone

umbellifer Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus '' Apium'' and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plant ...

species Honewort ('' Trinia glauca''). White Rock-rose (''

Helianthemum apenninum ''Helianthemum apenninum'', the white rock-rose, is a white-flowering rock rose of the family Cistaceae found in the North Atlantic region, mainly in dry grassy and rocky places across large parts of Europe. ''Helianthemum apenninum'', is a se ...

'') is found at the site and hybridises with Common 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 ...

'') to form the hybrid ''H. x sulphureum''. Forty species of grass occur at the site, including Somerset Hair-grass (''

Koeleria vallesiana ''Koeleria vallesiana'', the Somerset hair grass, is a grass species of the genus ''Koeleria''. It grows in Europe, temperate Asia, and North America North America is a continent in the Northern Hemisphere and almost entirely withi ...

'') which in Britain is confined to the western Mendips. Musk Stork's-bill ('' Erodium moschatum'') occurs here.Myles (2000), page 156 The

Mendip Way The Mendip Way is an long-distance footpath across the Mendip Hills from Weston-super-Mare to Frome. It is divided into two sections. The West Mendip Way was opened in 1979 and starts at the Bristol Channel at Uphill Cliff. It climbs the Me ...

crosses the site.

References

Bibliography

* Myles, Sarah (2000) ''The Flora of the Bristol Region''

Sources

English Nature citation sheet for the site
(accessed 17 July 2006) {{SSSIs Avon biological Sites of Special Scientific Interest in North Somerset Sites of Special Scientific Interest notified in 1990 Mendip Hills Hills of Somerset