Lower Bostraze and Leswidden

Also within

Cornwall County Cornwall Scenic Area

Condition (Natural England)

Geology & landscape

Rock Type: Granite

Landscape processes: Volcanic / Igneous

Description

Lower Bostraze and Leswidden SSSI Description The two discrete parts of this site, notified for the presence of a very rare liverwort, are located approximately eight kilometres west of Penzance. They are underlain by the Land’s End granite, part of the Cornubian batholith. Zones within the granite, altered by kaolinisation, have been extensively worked for china 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. The site supports important populations of the internationally rare liverwort western rustwort Marsupella profunda*. This species is presently known from only one other location in Britain, also in west Cornwall. Internationally, it is known from Portugal, the Canaries, Azores and Madeira, but it is rare throughout its range. 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 other bryophytes and by vascular plants.

Species mentioned