This vegetation type is dominated by Potamogeton gramineus, which has both broad leaves floating on the water surface and narrow submerged leaves. In some stands natant leaves can be absent, and in such cases the plants are entirely submerged. This association is typical of shallow mesotrophic water bodies with a mineral bottom, mainly fishponds but also flooded depressions and alluvial pools. It disappears in later successional stages characterized by mud accumulation. This is a rare vegetation type in the Czech Republic.