Vallisneria (named in honor of Antonio Vallisneri) is a genus of freshwater aquatic plant, commonly called eelgrass, tape grass or vallis. The genus is widely distributed in tropical and subtropical regions of Asia, Africa, Europe, and North America. Sometimes it is confused with the superficially similar Sagittaria when grown submerged. This plant should not be confused with Zostera species, marine seagrasses that are usually also given the common name "eelgrass".