- Lower Bostraze and Leswidden SSSI
Lower Bostraze And Leswidden SSSI is a
biological Site of Special Scientific Interest , located on thePenwith Peninsula ,Cornwall , a little to the east of St Just, approximately 8 km west ofPenzance .There are two discrete parts of this site - Lower Bostraze China Clay Works and Leswidden Block Works; together they are 23,000 m² in size. Lower Bostraze is located at gbmapping|SW385315, and Leswidden at gbmapping|SW390310.
The site was notified as an SSSI in 1996. The site lies within the
Cornwall Area of Outstanding Natural Beauty and thePenwith Heritage Coast and is partly within theWest Penwith Environmentally Sensitive Area .ite Description
Both parts of the site are underlain by the Land's End
granite , part of theCornubian batholith . Zones within the granite, altered bykaolinisation , have been extensively worked forchina clay until recent years. Both areas are located within disused china clay workings, consisting of pits, benches, spoil tips and granitic debris with sparse vegetation cover.Biological Interest
The site's SSSI status is due to the presence of important populations of a very rare liverwort, the
Western Rustwort "Marsupella profunda". This species is rare in a British context (it is known from only one other location inBritain, also in west Cornwall). However it is also internationally rare, being known only fromPortugal , theCanary Islands , theAzores and Madeira; throughout this range it is a rare specie.At Lower Bostraze and Leswidden, Western Rustwort is generally found growing on micaceous or clay waste substrates which are flat or gently sloping. Some patches occur on granitic rocks,usually where these are soft or crumbling. It appears to be a
pioneer species , the largest populations being found on surfaces showing the early stages of colonisation by otherbryophyte s and byvascular plant s.
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