Formations of waters dominated by rooted aquatic plants with floating leaves. The most typical species are Nuphar lutea, Nymphaea alba, Nymphoides peltata, Trapa natans and Persicaria amphibia, of the alliance Nymphaeion albae. A second layer is often formed by Ceratophyllum demersum, Myriophyllum spicatum and Lemna trisulca.