Ceratophyllum demersum (Rigid Hornwort)

Systematics :

Kingdom: Plantae
Artificial group: Vascular plant (Tracheophytes)
Superphylum: Spermatophyte
Phylum: Magnoliophyta
Subclass: Magnoliidae
Family: Ceratophyllaceae
Genus: Ceratophyllum
Species: Rigid Hornwort (Ceratophyllum demersum)

Norwegian name: Hornblad