Potamogeton friesii, known as
flat-stalked pondweed, or
Fries' pondweed, is an aquatic plant in the genus
Potamogeton. It grows mainly in mesotrophic to eutrophic rivers, lakes, ponds and ditches, rarely in brackish water. It occurs in North America, Europe, western Asia and a few scattered locations elsewhere in Asia.
(Wikipedia)