NVC community SD17 (Potentilla anserina - Carex nigra dune-slack community) is one of the 16 sand-dune communities in the British National Vegetation Classification system. It is one of five communities associated with dune slacks. It is a very localised community. There are four subcommunities. Community composition The following constant species are found in this community: Creeping Bent (Agrostis stolonifera) Common Sedge (Carex nigra) Silverweed (Potentilla anserina) Pointed Spear-moss (Calliergon cuspidatum) No rare species are associated with the community. Distribution This community is found in two areas - on the east coast, from Spurn Point to northwest Norfolk, and on the dunes of Liverpool Bay.And north Wales. Subcommunities There are three subcommunities: the Festuca rubra - Ranunculus repens subcommunity the Carex flacca subcommunity the Caltha palustris subcommunity the Hydrocotyle vulgaris - Ranunculus flammula subcommunity References Rodwell, J. S. (2000) British Plant Communities Volume 5 - Maritime communities and vegetation of open habitats (hardback), (paperback) SD17