Potamogeton subsibiricus |
Potamogeton amplifolius |
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potamot de l'ilenissei, Yenisei River pondweed, Yenissei River pondweed |
big-leaf pondweed, broad-leaf pondweed, large-leaf pondweed, potamot à grandes feuilles |
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Cauline stems | compressed-filiform, without spots, to 50 cm; glands white, 0.3–0.5 mm diam. |
terete, often rusty spotted, 6–110 cm; nodal glands absent. |
Turions | lateral, common, 3.5–9.5 cm × 2–5 mm, soft; leaves ± 2-ranked; outer leaves 3–4 per side, base not corrugate; inner leaves undifferentiated. |
absent. |
Leaves | submersed, ± spirally arranged, sessile, flaccid; stipules deliquescent, inconspicuous, convolute, free from blade, pale brown, not ligulate, 1–2 cm, not fibrous, not shredding, apex obtuse; blade dark green, linear, not arcuate, 3.5–9.5 cm × 1.5–2 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, rounded or nearly acute to mucronate, lacunae in 1–2 rows each side of midvein; veins 9–17. |
both submersed and floating or floating absent, ± spirally arranged. |
Floating leaves | petioles continuous in color to apex, 2.3–22.6 cm; blade adaxially light green, lanceolate to round elliptic, 4.3–9.2 cm × 25–38 mcm, base rounded to cordate, apex acute to rounded; veins 27–49. |
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Submersed leaves | petiolate, lax; stipules persistent, conspicuous, convolute, free from blade, light brown, not ligulate, 1.5–11.7 cm, not fibrous, not shredding at tip, apex acute; petioles terete, 0.9–11.5 cm; blade light to dark green, ovate to oblanceolate, distinctly arcuate, 5–12.5 cm × 15–58 mm, base rounded to acute, without basal lobes, not clasping, margins entire, crispate, apex not hoodlike, acute to round-apiculate, lacunae absent; veins 19–49. |
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Inflorescences | unbranched, emersed; peduncles not dimorphic, axillary, erect, cylindric, 1.7–3.5 cm; spikes not dimorphic, cylindric, 10–30 mm. |
unbranched, emersed; peduncles not dimorphic, terminal or axillary, erect, cylindric, 4.5–22.3 cm; spikes not dimorphic, cylindric, 34–65 mm. |
Fruits | sessile, reddish brown, oblong-obovoid, compressed, abaxially ridged, not laterally keeled, 3–4 × 1.5–2 mm; beak nearly erect, 0.3–0.5 mm; sides without basal tubercles; embryo with 1 full coil. |
sessile, reddish brown, obovoid, turgid, abaxially keeled, laterally ridged, 5–6.7 × 4.5–5.2 mm, lateral ridges without points; beak erect, 0.5–0.8 mm; sides without basal tubercles; embryo with full spiral. |
Rhizome(s) | absent. |
present. |
2n | = 52. |
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Potamogeton subsibiricus |
Potamogeton amplifolius |
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Phenology | Fruiting early summer–late summer. | Flowering summer–fall. |
Habitat | Shallow water of ponds and lakes | Waters of lakes, ponds, streams, and rivers |
Elevation | 0–915 m (0–3000 ft) | 0–1900(–2900) m (0–6200(–9500) ft) |
Distribution |
AK; MB; NT; NU; ON; QC; YT; Siberia |
AL; AR; CA; CT; GA; IA; ID; IL; IN; KS; MA; MD; ME; MI; MN; MO; MT; NC; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SD; TN; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; QC; SK
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Discussion | No specimens have been seen from Kentucky or Texas, but the species is to be expected there. Potamogeton amplifolius is common throughout much of North America. Its submersed leaves are larger than those of most other species of Potamogeton, are arcuate, and have more veins than do any other species. One hybrid, Potamogeton amplifolius × P. illinoensis (= P. × scoliophyllus Hagström), has been described. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 22. | FNA vol. 22. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | P. porsildiorum | |
Name authority | Hagström: Kongl. Svenska Vetenskapsakademiens Handlingar n.s. 44:555(5):84. (1916) | Tuckerman: American Journal of Science, and Arts ser. 2, 6:225. (1848) |
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