Hydrilla verticillata
Similar to Egeria densa Planch.
Brazilian Elodea can be easily mistaken for hydrilla. (Hydrilla verticillata), another highly invasive water species.
Brazilian Elodea is a very bushy plant with dense whorls of bright green leaves (except when growing in insufficient light, in which case the leaves are widely spaced). Brazilian elodea usually has four leaves per whorl (and each leaf is at least 0.8 in. (2 cm) long)
Hydrilla has five leaves per whorl and tiny spines along the leaf margins. The midrib of each leaf is often reddish. Hydrilla produces tubers (small potato-like structures). Neither Brazilian nor American waterweed produce tubers.