Fen

A fen is a peat-accumulating wetland fed by mineral-rich ground or surface water, which gives it a higher mineral content and a more basic pH than a bog; rich fens run near pH 7 to 5 while poor fens are more acidic, around pH 5.5 to 4. Because fens receive a continuous supply of minerals from groundwater rather than depending on precipitation alone, they support higher biodiversity and species richness than nutrient-poor bogs. Fens are dominated by sedges and mosses, particularly graminoids, with the sedge genus Carex and brown mosses typical of rich fens and Sphagnum moss more typical of poor fens, and woody vegetation is sparse or absent.