A perennial herb of calcareous mires, marshy grassland, water-meadows, flushes, Salix fen-carr and Alnus woods. 0-780 m (Cross Fell, Cumberland).
This species showed some losses before 1930 in the 1962 Atlas, and this decline has accelerated since then. This has followed the degradation or loss of its wetland habitats.
European Temperate element; also in C. Asia and N. America.