Knightsbridge Lane

Also within

Oxfordshire County

Condition (Natural England)

Geology & landscape

Geological Period: Cretaceous · Rock Type: Greensand

Description

Area, 1.7 hectares 4.3 ac Description This site, which consists of a strip of woodland bordering a minor road, supports one of the largest British populations of the very rare plant species, green hound's tongue Cynoglossum germanicum. The lane follows a parish boundary and is part of an ancient track known as the 'Ruggeway' which followed a route from London through the Chiltern escarpment to the clay lowlands beyond. It has soils consisting of stagnogleyic brown earths derived from the Cretaceous Gault and Upper Greensand. The woodland is composed of mixed broadleaved species, having a canopy dominated by pedunculate oak Quercus robur and ash Fraxinus excelsior and with a shrub layer of field maple Acer campestre, hawthorn Crataegus monogyna, hazel Corylus avellana, wayfaring tree Viburnum lantana and English elm Ulmus procera. There is considerable growth of tall weed species such as stinging nettle Urtica dioica and cleavers Galium aparine, together with woodland plants which include wood avens Geum urbanum, sanicle Sanicula europaea and sweet woodruff Galium odoratum. Green hound's tongue is a plant with a wide, but scattered, distribution in western, central and southern Europe and extending into Asia. In Britain the species has declined markedly since 1900 when it was widespread throughout central and southern England. It is now found in hedgerows and open woods in only eight localities in Surrey, Gloucestershire and Oxfordshire. The decline may be associated with climatic factors, or with changes in woodland management. The British Red Data Book of Vascular Plants classifies the species as vulnerable likely to become endangered if current trends continue. Green hound's tongue is a biennial species with spiny fruit's which can be dispersed on the fur of animals. It is often associated with disturbed soils and colonies in other areas are known to fluctuate with management cycles. At Knightsbridge Lane the species may have increased following disturbance associated with the clearance of dead elm and it is more frequent in the open woodland rather than amongst heavy shade. The site contains approximately one tenth of the British population.

Species mentioned