Potamogeton pusillus is a species of aquatic plant known by the common name small pondweed. It has a Circumboreal distribution, occurring throughout the northern Northern Hemisphere. It grows in water bodies such as ponds, lakes, ditches, vernal pools, and slow-moving streams. This is a superficially grasslike herb producing a very slender, branching stem easily exceeding one meter in length. The leaves are threadlike and delicate to linear and coarse, and measure a few centimeters in length....