Communities of the shores of shallow oligotrophic pools of the Atlantic domaine of Europe susceptible to prolonged summer desiccation, usually developed on peaty or parapeaty soils, dominated by, or rich in Baldellia ranunculoides, with Hydrocotyle vulgaris, Hypericum helodes. They are recorded, in particular, from the Paris Basin, Normandy, the New Forest, Cornwall, southern Scandinavia, and, on the shores of of limestone pools, in the Burren of western Ireland.