Siliceous screes of hills of western and central Europe, with Epilobium collinum, Galeopsis segetum, Acetosella vulgaris, Dalanum ladanum, Petasites albus, Tussilago farfara, Senecio viscosus, Anarrhinum bellidifolium, Cryptogramma crispa. Upland siliceous screes, often resulting from quarry activity, and colonised by very impoverished forms of the Alpine communities, usually rich in mosses, lichens and sometimes ferns, notably Cryptogramma crispa, or pioneer psammophilous grasses, are included. Vegetation of alliance Galeopsion segetum.