Fourleaf mare´s tail (Hippuris tetraphylla), an aquatic plant that grows in shallow and sheltered bays, is critically endangered (CR) in Sweden according to the Swedish red list. The first Swedish findings of the species were documented in 1996 in three locations, today only remaining in one. The species has most likely spread from Finland through seeds or stem fragments that have drifted across the northern Gulf of Bothnia. 

Hippuris tetraphylla. Photo: Anniina Saarinen. 

In Finland, H. tetraphylla is classified as vulnerable (VU) according to their red list, but with a much greater spread than in Sweden – 10 to 50 million sprigs as opposed to 6400 sprigs in Sweden. SeaMoreEco wants to develop restoration methods for endangered species like H. tetraphylla, through genetic mapping and translocation of the Finnish population to Sweden. For more information, see our article in Svensk Botanisk Tidsskrift.


Svenska Botaniska Föreningen (

Hippuris tetraphylla. Photo: Jonas Grahn.