Publication: Botanical Gazette. 5: 50. 1880.

Origin: Native

Herbarium search: CPNWH

Notes: FNA22: "Potamogeton illinoensis and P. gramineus are often difficult to separate. Certainly, in the extreme of each they are easily separated, but they continually grade into each other. Features to look for are the acute-mucronate apex of the submersed leaves of P. illinoensis and the acuminate apex for P. gramineus. Also, the number of veins seems to work as well.

Three hybrids, Potamogeton illinoensis x P. nodosus (= P. x faxonii Morong), P. amplifolius x P. illinoensis (= P. x scoliophyllus Hagström), and P. gramineus x P. illinoensis [= P. x spathuliformis (J. W. Robbins) Morong], have been described."

Last updated 9/17/2023 by David Giblin.