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