Spotted Pondweed

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.

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.

N.B., N.S., Ont. , P.E.I.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va., Wis.

Flowers summer--fall. Stagnant to slow-flowing waters of streams, lakes, ponds, and small rivers; 0--700m.

Potamogeton pulcher Tuckerm. Am. Jour. Sci
45: 38. 1843.
Potamogeton lucens fiuitans Robb. in A. Gray, Man. ed. 2. 435. 1856.
Stem simple, rarely branched; floating leaves petioled; blades coriaceous, ovate or orbicular-ovate, acute or obtuse at the apex and cordate or subcordate at the base, 4-10 cm. long, 3-7 cm. wide ; petioles as thick as the stem, 5-10 cm. long, rarely longer ; submerged leaves petiolate ; blades pellucid or semi-coriaceous, the upper lanceolate and the lower spatulate-ovate and sometimes narrowed into a winged petiole, 7-20 cm. long, much narrower than the floating leaf-blades ; stipules 2-keeled, acuminate or obtuse, 2.5-5 cm. long; spikes cylindric, 2.3-4 cm. long, densely flowered, but the fruit rarely maturing ; peduncles as thick as or a little thicker than the stem ; nutlets smooth, 3-keeled, the middle keel more prominent than the lateral ones ; style at least 2 mm. long ; embryo a complete spiral, the curved apex pointing inside the base.
Type locality : Medford, Massachusetts. %
Distribution : Massachusetts to British Columbia, south to Georgia and Arkansas.