This vegetation type, dominated by Hydrocharis morsus-ranae, occurs in shallow water bodies with mesotrophic to naturally eutrophic, still or slow-moving water such as that of oxbows, alluvial pools, fishpond margins, flooded sand pits in an advanced stage of terrestrialization, or channels. It is found in lowlands and colline areas of the Czech Republic, most frequently in the floodplains of large lowland rivers, such as the lower Vltava, middle Labe, lower Dyje and lower Morava.