Forests of Quercus robur and Fraxinus excelsior, rich in ligneous species, in particular, Fagus sylvatica, Carpinus betulus, Sorbus aria, Sorbus torminalis, Ulmus glabra (Ulmus scabra), Taxus baccata, Acer campestre, Cornus mas, Pyrus pyraster, Daphne laureola, characteristic of well-drained, often deep, sometimes rocky, moist or partly dry calcareous soils on gentle slopes of the south Paris basin and adjacent regions, with Arum italicum, Asarum europaeum, Doronicum plantagineum, Helleborus foetidus, Hepatica triloba, Orobanche hederae, Lilium martagon, Carex montana.