The genus Vallisneria is of "uncertain taxonomic diversity" as of 2008, but includes an estimated four to ten species worldwide.
Vallisneria is distributed widely the genus typically exhibits low regional diversity throughout its range, with the highest number of species reported in Australia.
A recent phylogenetic study of Hydrocharitaceae has indicated that Vallisneria, Maidenia Rendle, and Nechamandra Planch. are closely related and resolve as a well-supported and relatively derived clade within subfamily Hydrilloideae Luerss.
