Sparganium is a genus of flowering plants, containing about 20 species in temperate regions of both the Northern and Southern Hemispheres.
Branched S. erectum left,
Simplestem S..emersum right
Sparganium erectum is an emersed aquatic herb, to 1.5 m tall. It can be widespread hindering waterflow. Some authors have considered S. erectum L. to include the Eurasian population, as well as the North American population, called S. eurycarpum Engelm. Here, S. erectum is considered just the Eurasian population.
Usually Sparganium emersum will be smaller than the S. erectum species.