Sparse, bryophyte-poor, sedge and rush communities of bare, extremely wet peat muds of boreal mires, frequently inundated, remaining wet for a prolonged part of dry periods, together with pioneer communities of humid exposed peat or, sometimes, sand, forming on stripped areas of blanket bogs or raised bogs, as well as on naturally seep- or frost-eroded areas of wet heaths and bogs, in flushes and in the fluctuation zone of oligotrophic pools with sandy, slightly peaty substratum. Vegetation of alliance Rhynchosporion albae, the most typical species are Rhynchospora alba, Hydrocotyle vulgaris, Juncus bulbosus, Lycopodiella inundata, Sphagnum subsecundum, Sphagnum denticulatum and Sphagnum inundatum.