Potamogeton praelongus Wulfen
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Stems to 3 m, freely branched, usually flexuous or zigzag when the internodes are short (3–5 cm); lvs all submersed, sessile, lanceolate to lance-linear, 8–30 × 1–4.5 cm, obtuse or subacute and usually hooded at the tip, rounded and slightly clasping at base, with 11–35 veins, 3 or 5 of them stronger; stipules axillary, white, scarious, 3–8 cm, free but closely appressed to the stem, persistent, shredding at the tip; peduncles about as thick as the stem, usually elongate, to 5 dm; spikes cylindric, 3–7.5 cm, dense or interrupted; frs obovoid, turgid, 4–5.7 mm, short-beaked, with a sharp, narrow dorsal keel and often 2 obscure or rounded lateral ones; 2n=52. Usually in deep water; circumboreal, s. in Amer. to Conn., Md., Ind., Minn., Colo., and Calif.