Sparganium angustifolium-dominated formations of small oligotrophic ponds, characteristic, in particular, of the upper montane and subalpine levels of the Alps and of the greater Hercynian ranges, locally recorded from sub-Atlantic heath regions of the Germano-Baltic plain, also capable of occurring, within the extensive Fennoscandian range of the species, and in coastal areas of Iceland, as a facies of the Isoetes communities of unit C3.4111.