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Flat Stalked Pondweed

Potamogeton friesii Rupr.

Brief Summary

    Potamogeton friesii: Brief Summary
    provided by wikipedia

    Potamogeton friesii, known as flat-stalked pondweed, or Fries' pondweed, is an aquatic plant in the genus Potamogeton. It grows mainly in mesotrophic to eutrophic rivers, lakes, ponds and ditches, rarely in brackish water. It occurs in North America, Europe, western Asia and a few scattered locations elsewhere in Asia.

Comprehensive Description


    provided by eFloras
    Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Colo., Conn., Idaho, Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mont., Nebr., N.H., N.Y., N.Dak., Ohio, Pa., R.I., S.Dak., Utah, Vt., Wash., Wis., Wyo.; Eurasia.


    provided by eFloras
    Potamogeton friesii is a fairly common linear-leaved species, especially of calcareous waters of lakes and streams of the upper Midwest. Whenever turions are present, the species is easily identified, as it is the only one with the outer leaves of the turions having corrugate bases and the inner leaves turned at right angles to the outer leaves.

    Two hybrids, Potamogeton friesii ´ P. pusillus (= P. ´ pusilliformis Fischer [P. ´ intermedius Fischer]) and P. friesii ´ P. obtusifolius (= P. ´ semifructus A. Bennett ex Ascherson & Graebner), have been described.

    provided by eFloras
    Rhizomes absent. Cauline stems compressed, without spots, 10--135 cm; glands green, greenish brown, or gold, to 0.7 mm diam. Turions terminal or lateral, common, 1.5--5 cm ´ 1.5--4 mm, soft; leaves ± 4-ranked; outer leaves 2--3 per side, base corrugate, apex apiculate to acute; inner leaves reduced, arranged into fan-shaped structure and oriented at 90° angles to outer leaves. Leaves submersed, ± spirally arranged, delicate to rigid, sessile; stipules not persistent, inconspicuous, convolute, free from blade, white, not ligulate, 0.55--2.1 cm, fibrous, coarse, shredding at tip, apex obtuse; blade light green, rarely olive-green to .somewhat reddish, linear, not arcuate, 2.3--6.5 cm ´ 1.2--3.2 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute to apiculate, lacunae absent or 1 narrow row each side of midrib; veins 5--7(--9). Inflorescences unbranched, emersed; peduncles not dimorphic, terminal or axillary, erect or rarely recurved, slightly clavate, 1.2--4.1(--7) cm; spike not dimorphic, cylindric, 7--16 mm. Fruits sessile, olive-green to brown, obovoid, turgid, not abaxially or laterally keeled, 1.8--2.5 ´ 1.2--2 mm; beak erect, 0.3--0.7 mm; sides without basal tubercles; embryo with 1 full spiral. 2n = 26.


    provided by eFloras
    Calcareous to brackish waters of lakes and slow-flowing streams; 0--3100m.


    provided by eFloras
    Flowering and fruiting summer--fall.