Wet meadows and water-meadows of the lowlands of Britain, northern Germany, Poland, the Netherlands, Belgium, France and northwestern Spain, developed on nutrient-rich, acidocline alluvions of rivers and brooks with a fluctuating water regime in which Senecio aquaticus and Bromus racemosus are usually prominent, accompanied by a variable cortège; Potentilla palustris and Menyanthes trifoliata characterize mesotrophic stands, Ranunculus auricomus and Primula elatior somewhat more base-rich ones. Carex disticha is usually present and sometimes abundant, marking a transition towards Magnocaricion communities of unit D5.211. At higher altitudes, above 250 m, on base-poor soils, these communities evolve towards Polygonum bistorta-dominated communities of unit E3.415.