Siliceous cliff and rock communities of the montane level of the middle European Hercynian ranges, the Jura, the Alps and their periphery, of Atlantic regions of the European continent and the British Isles, with Saxifraga sponhemica, Biscutella laevigata, Asplenium septentrionale, Asplenium adiantum-nigrum, Asplenium billotii, Asplenium foreziense.