Potamogeton strictifolius |
Potamogeton foliosus |
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narrowleaf pondweed, potamot à feuilles raides, stiff-leaf pondweed, straight-leaf pondweed |
closed-leaf pondweed, leafy pondweed |
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Rhizomes | absent. |
absent. |
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Cauline stems | terete, without spots, 27–95 cm; glands white, green, greenish brown, or gold, to 0.3 mm diam. |
slightly compressed, without spots, 4–75 cm; glands rarely present, black to gold, to 0.5 mm diam. |
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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. |
uncommon, lateral or terminal, 0.9–2.5 cm × 0.6–2 mm, soft; outer leaves 1–3 per side, base not corrugate, apex acute to apiculate; inner leaves rolled into hardened fusiform structure. |
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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). |
submersed, ± spirally arranged, sessile, delicate; stipules persistent, inconspicuous, convolute, free from blade, greenish to brown or rarely white, not ligulate, 0.2–2.2 cm, delicate to fibrous, rarely shredding at tip, apex obtuse; blade pale green to olive-green, rarely somewhat reddish, linear, not arcuate, 1.3–8.2 cm × 0.3–2.3 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute to apiculate, rarely with bristle, lacunae rarely present, 0–2 rows each side of midrib; veins 1–3(–5). |
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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. |
unbranched, emersed; peduncles not dimorphic, in axils of proximal, rarely distal leaves, recurved, clavate, 0.3–1.1(–3.7) cm; spikes not dimorphic, capitate to cylindric, 1.5–7 mm. |
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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. |
pale green to olive-green or brown, obovate to nearly orbicular, turgid to concave, sessile, abaxially keeled, not laterally keeled, 1.4–2.7 × 1.1–2.2 mm, abaxial keel undulate, winglike; beak erect, 0.2–0.6 mm; sides without basal tubercles; embryo with 1 full spiral. |
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2n | = 26. |
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Potamogeton strictifolius |
Potamogeton foliosus |
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Phenology | Flowering and fruiting summer–fall. | |||||
Habitat | Alkaline waters of lakes and slow-moving streams | |||||
Elevation | 50–2000 m (200–6600 ft) | |||||
Distribution |
CT; IL; IN; MA; ME; MI; MN; ND; NE; NY; OH; PA; SD; UT; VA; VT; WI; WY; AB; MB; NB; ON; QC; SK; YT
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AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK; YT; Central America
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Discussion | 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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 22. | FNA vol. 22. | ||||
Parent taxa | Potamogetonaceae > Potamogeton | Potamogetonaceae > Potamogeton | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | P. strictifolius var. rutiloides | |||||
Name authority | A. Bennett: J. Bot. 40: 148. (1902) | Rafinesque: Medical Repository hexade 2, 5:354. (1808) | ||||
Web links |
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