Potamogeton berchtoldii var. tenuissimus (Mertens & W.D.J. Koch) Fernald
Potamogeton berchtoldii var. tenuissimus (Mertens & W.D.J. Koch) Fernald is a synonym sensu FNA Ed. Comm., 2000 of:
Potamogeton berchtoldii Fieber subsp. berchtoldii, an accepted subspecies name sensu WCSP.