Biorepository Data Portal

Rhizomes absent. Cauline stems conspicuously flattened ('wing-flattened'), without spots, 60--120 cm; glands absent or rarely present, when present, gold, 0.3 mm diam. Turions common, terminal or lateral, 4--7.5 ´ 2--4.5 cm, firm; leaves ± 2-ranked; outer leaves 3--4 per side, base not corrugate, apex acute; inner leaves undifferentiated. Leaves submersed, ± spirally arranged, sessile, rigid; stipules persistent, conspicuous, convolute, free from blade, white, not ligulate, 1.5--3.5 cm, fibrous, shredding at tip, apex obtuse to acuminate; blade light green, linear, not arcuate, 10--20 cm ´ 2--5 mm, base rounded, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, blunt, acuminate, or bristle-tipped, lacunae absent; veins 15--35. Inflorescences unbranched, emersed; peduncles not dimorphic, terminal, erect to ascending, occasionally recurved, cylindric, 2--5 cm; spikes not dimorphic, cylindric, 15--30 mm. Fruits light green to olive-green, quadrate-oblong or nearly orbicular, turgid, sessile, with abaxially keeled, not laterally keeled, 4--5 ´ 3--3.5 mm, keel winglike; beak erect, 0.6--1 mm; sides without basal tubercles; embryo with 1 full spiral. 2n = 52. Flowering summer--fall. Lakes, ponds, and slow streams; 0--15003000 m; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Calif., Conn., Idaho, Ill., Ind., Iowa, Kans., Maine, Mass., Mich., Minn., Mont., Nebr., Nev., N.H., N.J., N.Y., N.Dak., Ohio, Oreg., Pa., S.Dak., Utah, Vt., Wash., Wis., Wyo. One hybrid, Potamogeton zosteriformis ´ P. strictifolius, has been described and has been given the name P. ×haynesii Hellquist & G. E. Crow and is known from northern Michigan, Minnesota, Vermont, and southern Canada.

Perennial submersed aquatic herb 0.6 - 1.2 m tall Stem: freely branched, elongate, strongly flattened, jointed, usually without nodal glands. Leaves: submersed, more or less arranged spirally, stalkless, translucent, 10 - 20 cm long, 2 - 5 mm wide, linear with a rounded base and blunt to pointed tip (sometimes bristle-tipped), 15- to 35-veined, and firm. Stipules axillary, free from leaf blade, whitish, rolled up, 1.5 - 3.5 cm long, fibrous, shredding at tip. Inflorescence: a cylindrical spike with seven to eleven whorls of flowers, emersed, unbranched, 1.5 - 3 cm long, on a terminal stalk. Stalk often curved, cylindrical, 2 - 5 cm long, and firm. Flowers: greenish, tiny. Stamens four. Anthers two-chambered, with four edge-to-edge sepal-like outgrowths. Fruit: an achene, stalkless, light green to olive, 4 - 5 mm long, 3 - 3.5 mm wide, broadly elliptic to egg-shaped, plump, keeled, with an upright, 0.6 - 1 mm long beak. Keel wing-like.

Similar species: No information at this time.

Flowering: July to late August

Habitat and ecology: Frequent in streams 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. Zosteriformis means "similar to (the genus) Zostera."

Author: The Morton Arboretum

Stems elongate, freely branched, strongly compressed, 1-3 mm wide, mostly without nodal glands; rhizome scarcely developed; lvs all submersed, linear, 1-2 dm נ2-5 mm, acute or cuspidate, scarcely narrowed at base, with 1-3 main veins and numerous (to 35) very fine ones; stipular sheaths axillary, free, rather firm, 1-2 cm, obtuse to acuminate; winter-buds commonly produced, 4-7.5 cm, their lvs not strongly differentiated; peduncles stout, 2-5 cm, often curved; spike cylindric, 1.5-2.5 cm, with 7-11 whorls of fls; achenes broadly elliptic-ovoid, 4-4.5 mm, with a sharp but narrow, slightly dentate dorsal keel; 2n=52. Ponds and slow streams; Que. and N.B. to B.C., s. to Va., Ind., Io., and Calif. (P. compressus and P. zosterifolius, misapplied) A putative hybrid with no. 9 [Potamogeton strictifolius A. Benn] is P. بaynesii Hellq. (P. longiligulatus, misapplied)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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