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,
Sorbus aucuparia be applied to other species in "Sorbus" subgenus "Sorbus", and mountain ash may be used for several other distantly related trees. The species is unrelated to the true ash trees (genus "Fraxinus"), which also carry pinnate leaves or the species "Eucalyptus regnans", also called mountain ash, native to Tasmania and Victoria in southeastern Australia. "S. aucuparia" was previously categorized as "Pyrus aucuparia". The author citation "Sorbus aucuparia" L. belongs to Carl Linnaeus. "Sorbus aucuparia" occurs as a tree or shrub that grows up to between 5 and 15 m in height. The crown is loose and roundish or irregularly shaped