Narrow Leaved Pondweed

Potamogeton strictifolius is a relatively uncommon species found in alkaline waters. Fairly rigid leaves of the species make floating onto paper unnecessary in the collecting process. The leaves have a tendency to become revolute during the growing season. The species superficially resembles several other species of linear-leaved pondweeds. Consequently, many specimens of this species have been misidentified as other species and vice versa. Thus, literature records are often suspect.

One hybrid, Potamogeton strictifolius ´ P. zosteriformis (= P. ´ haynesii Hellquist & G. E. Crow), has been described.

Rhizomes absent. Cauline stems terete, without spots, 27--95 cm; glands white, green, greenish brown, or gold, to 0.3 mm diam. Turions terminal or lateral, common, 2.5--4.8 cm ´ 0.8--2.2 mm, soft; leaves ± 2-ranked, flattened with outer and inner leaves in same plane; outer leaves 3--4 per side, base not corrugate, or rarely corrugate, apex acute; inner leaves undifferentiated. Leaves submersed, ± spirally arranged, rigid, sessile; stipules disintegrating, inconspicuous, connate, free from blade, white, not ligulate, 0.6--1.6 cm, fibrous, shredding at tip, apex obtuse; blade green to olive-green, linear, not arcuate, 1.2--6.3 cm ´ 0.6--2 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute to nearly bristle-tipped, rarely obtuse to apiculate, lacunae absent; veins 3--5(--7). Inflorescences unbranched, emersed; peduncles not dimorphic, terminal, erect, rarely recurved, cylindric, rarely slightly clavate, 1--4.5 cm; spike not dimorphic, cylindric, 0.6--1.3 cm. Fruits sessile, green-brown, ovoid, turgid, not abaxially or laterally keeled, 1.9--2.1 ´ 1.3--1.8 mm; beak erect, 0.5--0.8 mm; sides without basal tubercles; embryo with 1 full spiral. 2n = 26.

Alta., Man., N.B., Ont., Que., Sask., Yukon; Conn., Ill., Ind., Maine, Mass., Mich., Minn., Nebr., N.Y., N.Dak., Ohio, Pa., S.Dak., Utah, Vta., Vat., Wis., Wyo.

Flowering and fruiting summer--fall.

Alkaline waters of lakes and slow-moving streams; 50--2000m.

Potamogeton strictifolius A. Bennett var. rutiloides Fernald

Potamogeton strictifolius, common names straight-leaved pondweed, pondweed, straight-leaf pondweed, and narrow-leaved pondweed, is a species of plant found in North America. It is listed as endangered in Connecticut, Illinois, Indiana, Massachusetts, and in New York (state). It is listed as possibly extirpated in Maine, and presumed extirpated in Ohio.