Potamogeton alpinus |
Potamogeton subsibiricus |
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alpine pondweed, northern pondweed, potamot alpin, reddish pondweed |
potamot de l'ilenissei, Yenisei River pondweed, Yenissei River pondweed |
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Cauline stems | terete, without spots, to 200 cm; nodal glands absent. |
compressed-filiform, without spots, to 50 cm; glands white, 0.3–0.5 mm diam. |
Turions | absent. |
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. |
Leaves | submersed and floating or floating absent, ± spirally arranged. |
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. |
Floating leaves | petioles continuous in color to apex, 0.1–1.2 cm; blade reddish green, elliptic or oblanceolate to obovate or oblong-linear, 4–7(–10) cm × 10–25(–40) mm, base gradually tapering into petiole, apex obtuse or acute; veins (7–)9–13(–15). |
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Submersed leaves | sessile, lax; stipules persistent, inconspicuous, convolute, free from blade, light brown to reddish, not ligulate, (1.2–)1.5–2.5(–4) cm, not fibrous, not shredding at tip, apex blunt; blade reddish green, oblong-linear to linear-lanceolate, not arcuate, 4.5–18(–25) cm × 5–20 mm, base rounded, without basal lobes, slightly clasping, margins entire, not crispate, apex not hoodlike, obtuse or acute, lacunae in 0–6 rows each side of midvein; veins 7–9. |
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Inflorescences | unbranched, emersed; peduncles not dimorphic, terminal or axillary, erect, cylindric, 3–10(–16) cm; spikes not dimorphic, cylindric, 10–35 mm. |
unbranched, emersed; peduncles not dimorphic, axillary, erect, cylindric, 1.7–3.5 cm; spikes not dimorphic, cylindric, 10–30 mm. |
Fruits | pedicellate, tawny olive-green, obovoid, plump, turgid, abaxially keeled, laterally keeled or not, (2.5–)3–3.5 × (1.7–)2–2.4 mm, lateral keels when present without points; beak abaxially curved, 0.5–0.9 mm; sides without basal tubercles; embryo with 1 full spiral. |
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. |
Rhizome | present. |
absent. |
2n | = 52. |
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Potamogeton alpinus |
Potamogeton subsibiricus |
|
Phenology | Flowering early summer–fall. | Fruiting early summer–late summer. |
Habitat | Ponds, lakes, and slow-moving streams | Shallow water of ponds and lakes |
Elevation | 400–2500 m (1300–8200 ft) | 0–915 m (0–3000 ft) |
Distribution |
AK; CA; CO; ID; MA; ME; MI; MN; MT; NH; NJ; NV; NY; OR; PA; SD; UT; VT; WA; WI; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; Greenland; Europe; Asia Eurasia
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AK; MB; NT; NU; ON; QC; YT; Siberia |
Discussion | Plants of Potamogeton alpinus often are red whenever taken from the water, a feature that makes this species quite distinctive. Two varieties, Potamogeton alpinus var. tenuifolius and var. subellipticus, have been recognized in North America, based mainly on submersed leaf shape. Plants bearing both leaf types have been observed in the same population; hence the varieties are not recognized. Four hybrids, Potamogeton alpinus × P. nodosus (= P. ×subobtusus Hagström), P. alpinus × P. gramineus (= P. xnericius Hagström), P. alpinus × P. praelongus (= P. ×griffithii A. Bennett), and P. alpinus × P. perfoliatus (= P. ×prussicus Hagström), have 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 | Potamogetonaceae > Potamogeton | Potamogetonaceae > Potamogeton |
Sibling taxa | ||
Synonyms | P. alpinus subsp. tenuifolius, P. alpinus var. subellipticus, P. alpinus var. tenuifolius, P. tenuifolius, P. tenuifolius var. subellipticus | P. porsildiorum |
Name authority | Balbis: Misc. Bot. 13. (1804) | Hagström: Kongl. Svenska Vetenskapsakademiens Handlingar n.s. 44:555(5):84. (1916) |
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