Purn Hill
Purn Hill is a 6.1 hectare biological Site of Special Scientific Interest near the village of Bleadon, Somerset, notified in 1990. The site is a small promontory of Carboniferous Limestone projecting southward from the main Mendip 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, Dropwort, Fairy Flax, Kidney Vetch and Dwarf Thistle. The rare plants are mainly associated with the small exposures of dolomitic limestone in the southern part of the site. Purn Hill is one of only five British sites for the nationally rare coastal limestone umbellifer species Honewort. White Rock-rose is found at the site and hybridises with Common Rock-rose to form the hybrid H. x sulphureum. Forty species of grass occur at the site, including Somerset Hair-grass which in Britain is confined to the western Mendips. Musk Stork's-bill occurs here.
The Mendip Way crosses the site.
