Elodea canadensis - Canadian Waterweed

Common in lakes, ponds and streams. May grow to nuisance densities in nutrient-rich waters. Looks similar to non-native invasives Egeria and Hydrilla. Elodea canadensis has blunt-ended leaves in whorls of 3, whereas Egeria and Hydrilla have leaves with acute (more pointed) tips arranged in whorls of four. Hydrilla leaves are also have sharply serrated edges.

Comparison between Elodea, Egeria and Hydrilla

Vallesneria americana - Tapegrass

Similar in appearance to some species of Sparganium, the two genera can be distinguished when flowering structures are present. Vallesneria has a single submerged flower on a long stalk which extends nearly to the surface, whereas Sparganium has bur-like flowers and fruiting bodies at the end of a leaf stalk. In the abscence of fruiting bodies, the plants can sometimes be distinguished by the leaf vein structure. Vallesneria has a prominant lacunae band (specialized air tissue) in the center of the leaf, whereas Sparganium does not.