A community of plants growing in basic or neutral waterlogged conditions, as opposed to a bog. This wetlands community, characterized by alkaline conditions, grows in zones between fresh water and land, as along lake margins. Fens represent a stage in the progressive colonization of shallow water; this plant succession continues with the colonization by trees (the 'carr' stage) followed in some areas by the growth of a raised bog on top of the fen and carr. This low land is subject to frequent inundations and is a very good source of artifactual information.