Kongl. Svenska Vetenskapsakademiens Handlingar n.s. 55(5): 127. 1916.
Rhizomes absent. Cauline stems terete, without spots, 20–50 cm; glands white, 0.1–0.7 mm diam. Turions terminal or axillary, common, 4.2–8.4 cm × 1.4–2.5 mm, soft; leaves ± 4-ranked; outer leaves 2 per side, base without corrugations, apex acute to apiculate; inner leaves unmodified. Leaves submersed, ± spirally arranged, sessile, delicate; stipules deliquescent to persistent, inconspicuous, convolute, free from blade, brown, not ligulate, 0.45–1.91 cm, not fibrous, not shredding at tip, apex obtuse; blade pale to deep green, linear, not arcuate, 2.6–8.8 cm × 0.7–1.7 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute to apiculate, lacunae absent or present, 0–3 rows each side of midrib; veins 7–11. Inflorescences unbranched, emersed; peduncles not dimorphic, terminal, erect, cylindric, 20 mm; spikes not dimorphic, cylindric, 5 mm. Fruits not laterally keeled, 2.6–2.7 × 2 mm; beak erect, 0.3 mm; sides without basal tubercles; embryo with 1 full coil. 2n = 26.
Phenology: Flowering late summer.
Habitat: Ponds and lakes
Elevation: 10–450 m
Of conservation concern.