Potamogeton richardsonii is a species of aquatic plant known by the common name Richardson's pondweed. It is native to much of northern North America, including all of Canada and the northern and western United States. It grows in water bodies such as ponds, lakes, ditches, and streams. This perennial herb grows a narrow, mostly unbranched stem from a mat of rhizomes in the substrate. It reaches about a meter in maximum length. The leaves are up... (Wikipedia)