Potamogeton compressus
 Potamogeton compressus is a species of aquatic plant known by the common names flatstem pondweed and eel-grass pondweed. It is native to much of northern North America including most of Canada and the northern United States. It grows in water bodies such as ponds lakes and slow-moving streams. This plant produces a very narrow flattened winged stem up to a roughly a meter in maximum length. The rigid light green leaves are linear in shape up to 20 centimeters long but less than 1 wide.