Rhizomes present. Cauline stems terete, conspicuously spotted, 8--95 cm; nodal glands absent. Turions absent. Leaves both submersed and floating, ± spirally arranged. Submersed leaves petiolate, lax; stipules deliquescent, inconspicuous, convolute, free from blade, light to dark brown, not ligulate, 0.7--1.2 cm, not fibrous, not shredding at tip, apex obtuse; petioles 0.5--4.5 cm; blade dark green, linear-lanceolate to lanceolate, often arcuate, 3.5--13.8 cm ´ 60--165 mm acute, base acute to rounded, without basal lobes, margins entire, crispate, apex not hoodlike, acute to obtuse, lacunae in 2--5 rows each side of midrib; veins 7--19. Floating leaves: petioles continuous in color to apex, 1--16.5 cm; blade adaxially light to dark green, lanceolate to round-ovate, 2.5--8.5 cm ´ 11--44 mm, base rounded to cordate, apex acute to rounded; veins 15--21. Inflorescences unbranched, emersed; peduncles not dimorphic, terminal or axillary, erect to ascending, cylindric, 3.3--9.4 cm; spikes not dimorphic, cylindric, 17--36 mm. Fruits sessile, dark green to dark brown, ovoid to obovoid, turgid, abaxially keeled, laterally ridged, 5--6.5 ´ 4.1--5 mm, lateral ridges without points; beak erect, 0.5 mm; embryo with 1 full spiral. Chromosome number apparently unknown not available.
Potamogeton pulcher is similar in morphology to P. amplifolius and occurs in similar habitats. Potamogeton pulcher differs from P. amplifolius by the former having lanceolate to linear-lanceolate submersed leaves with fewer than 19 veins, whereas the latter has ovate submersed leaves with more than 19 veins.
Perennial submersed aquatic herb with rhizomes to 0.5 m tall Stem: unbranched, jointed, with conspicuous black spots. Inflorescence: an upright, dense, cylindrical spike of flowers, emersed, unbranched, 1.5 - 4 cm long, on a terminal or axillary stalk. Stalk cylindrical, 3 - 12 cm long, a bit thicker than stem. Flowers: greenish, tiny. Stamens four. Anthers two-chambered, with four edge-to-edge sepal-like outgrowths. Fruit: an achene, stalkless, dark brown to dark green, 5 - 6.5 mm long, 4 - 5 mm wide, egg-shaped to reverse egg-shaped, plump, flat-sided, 3-keeled, with an upright, 0.5 mm long beak. Submersed leaves: more or less arranged spirally, on a 0.5 - 4.5 cm long stalk, translucent, 3.5 - 15 cm long, 1 - 3 cm wide, narrowly lance-shaped to lance-shaped with a rounded to tapering base and blunt to long-pointed tip, often arching, seven- to nineteen-veined, wavy along the margins. Stipules axillary, free from leaf blade, brownish, rolled up, to 6 cm long. Floating leaves: more or less arranged spirally, on a 1 - 16.5 cm long stalk, 2.5 - 8.5 cm long, 1 - 5 cm wide, lance-shaped to rounded egg-shaped with a heart-shaped to rounded base and rounded to pointed tip, 15- to 21-veined, leathery, firmer than submersed leaves.
Similar species: Potamogeton amplifolius is similar but differs by its higher number of veins on the submersed leaves. Also, the leaves differ in shape.
Flowering: June to early July
Habitat and ecology: Very rare in the Chicago Region. Found in marshes, ponds, swales, and lakes.
Occurence in the Chicago region: native
Notes: Plants in the genus Potamogeton are very important to wildlife, offering habitat and food for many aquatic animals.
Etymology: Potamogeton comes from the Greek words potamos, meaning river, and geiton, meaning neighbor, referring to the habitat of these plants. Pulcher means pretty, or handsome.
Stems rarely over 5 dm, simple, black-spotted; submersed lvs narrowly lanceolate, undulate-margined, 8-15 נ1-3 cm, 9-19-veined, long-acuminate, tapering at base to a poorly defined petiole; floating lvs broadly elliptic or oval, 4-8 נ2-5 cm, many-veined, obtuse, the base broadly obtuse to subcordate; petioles stout, black-spotted, 2-8 cm; stipules axillary, free, to 6 cm, cuspidate to long-acuminate; peduncles 5-12 cm, somewhat thicker than the stem; spike dense, cylindric, 2-4 cm; frs obliquely obovoid, 3.5-4.5 mm (beak included), with flat sides and 3 low, sharp dorsal keels. Shallow, acid waters and muddy shores; s. Me. to Fla. and Ala., chiefly near the coast; s. Ind. to Mo. and Ark. Shore-forms may lack lvs of the submersed type.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.