Potamogeton nodosus |
Potamogeton amplifolius |
|
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loddon's pondweed, long-leaf pondweed, pondweed, potamot noeuex |
big-leaf pondweed, broad-leaf pondweed, large-leaf pondweed, potamot à grandes feuilles |
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Rhizomes | present. |
present. |
Cauline stems | terete, without spots, to 100 cm; nodal glands absent. |
terete, often rusty spotted, 6–110 cm; nodal glands absent. |
Turions | absent. |
absent. |
Leaves | both submersed and floating, or floating absent, ± spirally arranged. |
both submersed and floating or floating absent, ± spirally arranged. |
Floating leaves | petioles 3.5–26 cm; blade adaxially light green, lenticular to elliptic, 3–11 cm × 15–45 mm, base cuneate to rounded, apex acute to rounded; veins 9–21. |
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. |
Submersed leaves | petiolate, lax; stipules persistent to deliquescent, conspicuous, convolute, free from blade, light brown, not ligulate, 3–9 cm, not fibrous, not shredding at tip, apex round to acute; petioles 2–13 cm; blade light to dark green, linear-lanceolate to lance-elliptic, not arcuate, 9–20 cm × 10–35 mm, base acute, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute, without sharp awl-like tip, lacunae in 2–5 rows each side of midrib; veins 7–15. |
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. |
Inflorescences | unbranched, emersed; peduncles not dimorphic, terminal, erect to ascending, cylindric, 3–15 cm; spikes not dimorphic, cylindric, 20–70 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, red to reddish brown, obovoid, abaxially keeled, laterally ridged, 2.7–4.3 × 2.5–3 mm, keel well developed, lateral ridges with blunt to sharp tips; beak erect; sides without basal tubercles; embryo with 1 full spiral. |
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. |
2n | = 52. |
= 52. |
Potamogeton nodosus |
Potamogeton amplifolius |
|
Phenology | Flowering summer–fall. | Flowering summer–fall. |
Habitat | Clear to turbid waters of lakes, streams, rivers, and sloughs | Waters of lakes, ponds, streams, and rivers |
Elevation | 0–3300 m (0–10800 ft) | 0–1900(–2900) m (0–6200(–9500) ft) |
Distribution |
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; NB; ON; QC; SK; Mexico; Central America; South America; West Indies; Eurasia
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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 | Six hybrids, Potamogeton gramineus × P. nodosus (= P. × argutulus Hagström), P. illinoensis × P. nodosus (= P. × faxonii Morong), P. nodosus × P. richardsonii (= P. × rectifolius A. Bennett), P. natans × P. nodosus (= P. × schreberi Fischer [P. × perplexus A. Bennett]), P. alpinus × P. nodosus (= P. × subotusus Hagström), and P. epihydrus × P. nodosus (= P. × subsessilis Hagström), have been described. Potamogeton nodosus is a common floating-leaved species throughout much of the United States and southern Canada. When both submersed and floating leaves are present, it is very easily recognized by the petioles of the submersed leaves being longer than 5 cm. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 22. | FNA vol. 22. |
Parent taxa | Potamogetonaceae > Potamogeton | Potamogetonaceae > Potamogeton |
Sibling taxa | ||
Name authority | Poiret: in J. Lamarck et al., Encyclopedie Methodique. Botanique... Supplement 4(2): 5354. (1816) | Tuckerman: American Journal of Science, and Arts ser. 2, 6:225. (1848) |
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