Calciphile wet meadows of Western Europe, Central Europe and northwestern Eastern Europe, northeast at least to Estonia, dominated by or rich in Juncus subnodulosus, characteristic of very wet calcareous soils or soils flushed by calcareous waters, transitional to the small sedge fens of the Caricion davallianae (unit D4.1), surviving mostly in the British Isles, in the Alpine foothills, in the moraine land of northern Germany, in chalk hills of northwestern Germany, in northern Jutland, on Fyn, in southern and central Scania, on Åland, in wet dune slacks of the Atlantic and North Sea seaboard of the continent of Europe; many formations are rather oligotrophic and could equally be listed under unit E3.5. Typical of these communities are the Juncus subnodulosus-Cirsium palustre fen-meadows, widespread in the southern British lowlands, particularly in East Anglia, north Buckinghamshire and Angelsey, rich in Juncus subnodulosus, Cirsium palustre, Equisetum palustre, Filipendula ulmaria, Holcus lanatus, Lotus uliginosus, Mentha aquatica, Caliergon cuspidatum; a characteristically variable species-rich cortège, influenced by the various grazing and mowing routines the meadows are subjected to, may include, among others, Trifolium spp., Briza media, Carex elata, Iris pseudacorus, Molinia caerulea, Dactylorhiza fuchsii, Dactylorhiza praetermissa, Dactylorhiza incarnata. Also particularly characteristic are the Juncus subnodulosus formations that succeed fen communities of unit D4.1 in the colonization of coastal wet dune slacks.