Forests analogous to those of the Ilici-Fagion but dominated by Quercus petraea or Quercus robur, often accompanied by Fagus sylvatica. They differ from unit G1.81 by the representation of the group of Maianthemum bifolium in the herb layer.
Quercus petraea or Quercus robur forests of Brittany, generally richer in epiphytes, mosses and evergreen shrubs than the forests of unit G1.821, transitional to unit G1.83.