ribbon-leaved pondweed

Potamogeton epihydrus is a perennial aquatic plant known by the common name ribbonleaf pondweed, Nuttall's pondweed (not to be confused with Elodea nuttallii) or in Britain and Ireland American pondweed. It is native to much of North America, where it grows in water bodies such as ponds, lakes, ditches, and slow-moving streams.