Potamogeton praelongus is a distinctive species with broad, sessile submersed leaves and no floating leaves. The stipules are large and persistent (see "stem and leaves" photo above) and the leaf tips are "boat-shaped" or cupped when fresh. If the leaves are pressed flat in vouchers, the boat-shaped tips often split, providing a helpful character for identification.

P. praelongus is fairly common in northern and eastern Wisconsin. Its absence from SW Wisconsin may be due to its preference for lakes. There are far fewer natural lakes in the SW counties.