This association includes open, currently usually tall-growing forests of Quercus petraea agg. and/or Q. robur. In most places the shrub layer is poorly developed, while the herb layer is species-rich, consisting of species adapted to an intermittent moisture regime (many of them shared with the Molinion caeruleae meadows), species of thermophilous and acidophilous oak forests and oak-hornbeam forests. It occurs mainly on gentle slopes or flatland with heavy, clayey soils with a broad pH range, which are wet in spring but dry in periods of low or infrequent rainfall in summer. In the Czech Republic this association is distributed mainly on Cretaceous sediments of northern and eastern Bohemia, but also on colluvial loamy sediments and loess accumulations in the Bohemian Karst, southern Moravia and some other areas.