This plant is severely threatened and even extinct in many regions where it was previously found. Since it needs an even supply of water, changes in the biotope which affects water supply prove damaging. The draining or drying out of swamps and marshes can be particularly damaging for this plant. In Sweden, it is today only found in the islands Öland and Gotland as well as parts of Skåne, where it is a threatened species. In Norway, it is now considered extinct, having not been observed since 1933. In Finland, it is today only found in the island of
Åland. == References ==