Backstone Bank and Baal Hill Woods one side valley, there is a small population of small-leaved lime, "Tilia cordata", which occurs here close to its northern limit and at an unusually high altitude. On base-rich soils, the woodland typically consists of ash, "Fraxinus excelsior", and wych elm, "Ulmus glabra", over an understorey of hazel, "Corylus avellana", and bird cherry, "Prunus padus", and a rich ground flora that includes lady-fern, "Athyrium filix-femina", male fern, "Dryopteris filix-mas", and hard shield-fern, "Polystichum aculeatum". On more acid soils, sessile oak, "Quercus petraea", and birch, "Betula sp.", are dominant. The under-storey, of hazel, holly, "Ilex aquifolium", rowan, "Sorbus aucuparia", and hawthorn,
Venusia cambrica The larvae feed on the leaves of "Sorbus aucuparia". Other recorded foodplants include alder, apple, birch, mountain ash, serviceberry and willow. Venusia cambrica Venusia cambrica, the Welsh wave, is a moth of the family Geometridae. It is found in Europe, western and central Siberia, Altai, Transbaikalia, the Russian Far East, the Korean Peninsula, Japan and in North America, where it can be found across Canada from Newfoundland and Labrador to British Columbia, south in the west to California, south in the east to Georgia. The wingspan is 27–30 mm. The light grey front wing has black and brown cross lines.