Fig. 204. <i>Potamogeton filiformis</i> from the second edition of <i><a href="//commons.wikimedia.org/wiki/Britton_%26_Brown,_Illustrated_Flora,_Second_Edition" title="Britton &amp; Brown, Illustrated Flora, Second Edition">An Illustrated Flora of the Northern United States, Canada and the British Possessions</a></i> (New York, 1913).<br>Note that <i><b>Potamogeton filiformis</b></i> Pursh ex Tuck., Amer. J. Sci. Arts, II, 6: 230 (1848), sensu auct. is now considered to be a synonym for the accepted species name: <i><b><a href="//commons.wikimedia.org/w/index.php?title=Potamogeton_gramineus&amp;action=edit&amp;redlink=1" class="new" title="Potamogeton gramineus (page does not exist)">Potamogeton gramineus</a></b></i> L., Sp. Pl.: 127 (1753).
Nathaniel Lord Britton &amp; Addison Brown
1913
An Illustrated Flora of the Northern United States, Canada and the British Possessions, 2nd edition (1913)