Sparganium emersum
Systematics :
Kingdom: Plantae
Artificial group: Vascular plant (Tracheophytes)
Superphylum: Spermatophyte
Phylum: Magnoliophyta
Class: Liliopsida
Family: Sparganiaceae
Genus: Sparganium
Species: Sparganium emersum
Other names: stautpiggknopp
Norwegian name: Rankpiggknopp