This association includes low-growing, open stands of Quercus petraea agg., with a sparse shrub layer or without a shrub layer altogether. The herb layer is usually dominated by the grasses Avenella flexuosa or Festuca ovina; it contains generalist acidophilous species but also some slightly thermophilous species. This is the association of acidophilous oak forests. It occurs on sunny slopes and around outcrops of poorly weathering acidic rocks in habitats that are usually slightly cooler or wetter than those of the association Sorbo torminalis-Quercetum.