- Purn Hill
Infobox SSSI
name=Purn Hill
aos=Avon
interest=Biological
gridref=ST332573
area=6.1hectare
notifydate=1990http://www.natureonthemap.org.uk/map.aspx?
]
Purn Hill (gbmapping|ST332573) is a 6.1
hectare biological Site of Special Scientific Interest near the village ofBleadon ,Somerset , notified in 1990. The site is a smallpromontory ofCarboniferous 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 ("Sanguisorba minor"),Dropwort ("Filipendula vulgaris"),Fairy Flax ("Linum catharticum"),Kidney Vetch ("Anthyllis vulneraria") andDwarf Thistle ("Cirsium acaule"). The rare plants are mainly associated with the small exposures ofDolomitic limestone in the southern part of the site. Purn Hill is one of only five British sites for the nationally rare coastal limestoneumbellifer speciesHonewort ("Trinia glauca").White Rock-rose ("Helianthemum apenninum") is found at the site and hybridises withCommon Rock-rose ("H. nummularium") to form the hybrid "H. x sulphureum". [Myles (2000) page 93] Forty species of grass occur at the site, includingSomerset Hair-grass ("Koeleria vallesiana") which in Britain is confined to the western Mendips.Musk Stork's-bill occurs here. [Myles (2000), page 156]References
Bibliography
* Myles, Sarah (2000) "The Flora of the Bristol Region" ISBN 1-874357-18-8
ource
* [http://www.english-nature.org.uk/citation/citation_photo/1000697.pdf English Nature citation sheet for the site] (accessed 17 July 2006)
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