Rhizomes present; cauline stems terete, with dark spots, 8–95 cm long. Turions absent. Nodal glands absent. Leaves submersed and floating, although either type may be absent on certain individuals, alternate, more or less spiraling. Submersed leaves petiolate; ligules conspicuous, free from blade, light brown, not fibrous, not shredding apically, deliquescent, convolute, 0.7–1.2 cm long, the apex obtuse; petiole compressed, 0.5–4.5 cm; dark green, linear lanceolate to lanceolate, often arcuate, 3.5–13.8 cm long, 6–165 mm wide, with 7–19 veins, 2–5 rows of lacunae each side of midrib, the base cuneate to obtuse, not clasping, without basal lobes, the margins undulate to crispate, the apex acute to obtuse, without a bristle tip, not cucullate. Floating leaves petiolate; petiole continuous in color to apex, terete, 1–16.5 cm long; leaf blade adaxially light green to dark green, lanceolate to round ovate, 2.5–8.5 cm long, 11–44 mm wide, the veins 15–21, the base obtuse to cordate, the apex acute to obtuse, without terminal bristle. Inflorescences unbranched, distal only; distal peduncles cylindrical, turgid, axillary or terminal, erect to ascending, 3.3–9.4 cm long; spikes emersed, cylindrical, 1.7–3.6 mm long, the nodes 7–19, the internodes 1.5–3 mm long. Flowers alternate to whorled; perianth spathulate, clawed, the claw 0.5–0.8 mm long, the blade 1–1.7 mm long, 1.8–2.3 mm wide; anthers 0.8–1.2 mm long; carpels 4. Fruiting gynophore absent. Fruits obovate to ovate, olive green to dark brown, turgid, abaxially angled, laterally angled, 5–6.5 mm long, 4.1–5 mm wide; abaxial angles keeled; lateral angles ridged, without sharp points; beak erect, ca. 0.5 mm long; tubercules absent; embryo ca. one full spiral.

Flowers summer--autumn. Stagnant to slow-flowing waters of streams, lakes, ponds, and small rivers; 5--500 m; N.S., Ont.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va., Wis.

This is a species similar in morphology to Potamogeton amplifolius and occurring in similar habitats. Potamogeton pulcher differs from P. amplifolius by the former having lanceolate to linear lanceolate submersed leaves that mostly have fewer than 19 veins, whereas the latter has mostly ovate submersed leaves that mostly have more than 19 veins.