Potamogeton foliosus Raf.

Rhizomes absent. Cauline stems slightly compressed, without spots, 4--75 cm; glands rarely present, black to gold, to 0.5 mm diam. Turions uncommon, lateral or terminal, 0.9--2.5 cm ´ 0.6--2 mm, soft; outer leaves 1--3 per side, base not corrugate, apex acute to apiculate; inner leaves rolled into hardened fusiform structure. Leaves submersed, ± spirally arranged, sessile, delicate; stipules persistent, inconspicuous, convolute, free from blade, greenish to brown or rarely white, not ligulate, 0.2--2.2 cm, delicate to fibrous, rarely shredding at tip, apex obtuse; blade pale green to olive-green, rarely somewhat reddish, linear, not arcuate, 1.3--8.2 cm ´ 0.3--2.3 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute to apiculate, rarely with bristle, lacunae rarely present, 0--2 rows each side of midrib; veins 1--3(--5). Inflorescences unbranched, emersed; peduncles not dimorphic, in axils of proximal, rarely distal leaves, recurved, clavate, 0.3--1.1(--3.7) cm; spikes not dimorphic, capitate to cylindric, 1.5--7 mm. Fruits pale green to olive-green or brown, obovate to nearly orbicular, turgid to concave, sessile, abaxially keeled, not laterally keeled, 1.4--2.7 ´ 1.1--2.2 mm, abaxial keel undulate, winglike; beak erect, 0.2--0.6 mm; sides without basal tubercles; embryo with 1 full spiral.

Potamogeton foliosus Raf. Med. Repos. II. 5 : 354. 1808
Polamogeton gramineus Michx. Fl. Bor. Am. 1 : 102. 1803. Not P. gramineus L. 1753.
? Potamogeton ex stipulation Muhl. Cat. 18. 1813.
Potamogeton paucifiorus Pursh, Fl. Am. Sept 121, 1814.
"Potamogeton niagarensis Tuckerm. Am. Jour. Sci. II. 7 : 354. 1849.
Potamogeton foliosus niagarensis A. Gray, Man. ed. 2. 435. 1856.
Potomogeton foliosus californicus Morong, Bot. Gaz. 10 : 254. 1885.
Potamogeton californicus Piper, Contr. U. S. Nat. Herb. 11 : 98, 1906.
Stems flattened, much branched, very rarely with propagating buds ; leaves all submerged, linear, 1.5-8 cm. long, 0.4-2 mm. wide, with an obtuse or more or less pungent apex, 3-5-nerved, the midrib prominent ; stipules axillary and free from the leaf -bases, obtuse or acute, 1.3-2.4 cm. long; spikes few-flowered, usually not more than 12 nutlets maturing ; peduncles usually 1-2 cm. long, as thick as or thicker than the stem ; nutlets pitted, 3-keeled, the middle keel winged and more or less dentate ; embryo an incomplete spiral, the apex pointing towards the base or outside it.
Type locality : Carolina.
Distribution: New Brunswick to British Columbia, south to Florida and Mexico; also in

Potamogeton foliosus is a species of aquatic plant known by the common name leafy pondweed. It is native to nearly all of North America and parts of Central America, where it grows in water bodies such as ponds, lakes, ditches, and slow-moving streams. It has been reported from every state in the United States except Hawaii as well as from every Canadian province and territory except Newfoundland and Nunavut.

Potamogeton foliosus is a perennial herb growing from a dense, mat-forming rhizome that anchors in wet substrate. It produces a thin, compressed, multibranched stem growing to a maximum length around 75 centimeters. The delicate, hairlike leaves are up to 10 centimeters long. They are pale green to olive green or reddish in color. The inflorescence is a small cluster or spike of flowers arising from the water on a short peduncle. Turions are sometimes present.

Potamogeton foliosus là một loài thực vật có hoa trong họ Potamogetonaceae. Loài này được Raf. miêu tả khoa học đầu tiên năm 1808.