This alliance includes species-poor communities of dystrophic bog hollows co-dominated by Carex limosa. C. rostrata, Eriophorum angustifolium and Scheuchzeria palustris. The herb layer is sparse, but bryophytes can reach cover values up to 100%. In areas of air pollution some Sphagnum species can be substituted by hepatics (e.g. Gymnocolea inflata) and algae. Bog hollows are maintained by the action of frost and water input from precipitation. This alliance is distributed in the boreal zone of northern Europe and mountainous areas of central Europe, but rarely it occurs also at lower altitudes in central and western Europe.