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narrowleaf pondweed, potamot à feuilles raides, stiff-leaf pondweed, straight-leaf pondweed

heartleaf pondweed, potamot gracieux, spotted pondweed

Rhizomes

absent.

present.

Cauline stems

terete, without spots, 27–95 cm;

glands white, green, greenish brown, or gold, to 0.3 mm diam.

terete, conspicuously spotted, 8–95 cm;

nodal glands absent.

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.

absent.

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).

both submersed and floating, ± spirally arranged.

Floating leaves

petioles continuous in color to apex, 1–16.5 cm;

blade adaxially light to dark green, lanceolate to round-ovate, 2.5–8.5 cm × 11–44 mm, base rounded to cordate, apex acute to rounded;

veins 15–21.

Submersed leaves

petiolate, lax;

stipules deliquescent, inconspicuous, convolute, free from blade, light to dark brown, not ligulate, 0.7–1.2 cm, not fibrous, not shredding at tip, apex obtuse;

petioles 0.5–4.5 cm;

blade dark green, linear-lanceolate to lanceolate, often arcuate, 3.5–13.8 cm × 60–165 mm acute, base acute to rounded, without basal lobes, margins entire, crispate, apex not hoodlike, acute to obtuse, lacunae in 2–5 rows each side of midrib;

veins 7–19.

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, terminal or axillary, erect to ascending, cylindric, 3.3–9.4 cm;

spikes not dimorphic, cylindric, 17–36 mm.

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.

sessile, dark green to dark brown, ovoid to obovoid, turgid, abaxially keeled, laterally ridged, 5–6.5 × 4.1–5 mm, lateral ridges without points;

beak erect, 0.5 mm;

embryo with 1 full spiral.

Chromosome number

apparently unknown not available.

2n

= 26.

Potamogeton strictifolius

Potamogeton pulcher

Phenology Flowering and fruiting summer–fall. Flowers summer–fall.
Habitat Alkaline waters of lakes and slow-moving streams Stagnant to slow-flowing waters of streams, lakes, ponds, and small rivers
Elevation 50–2000 m (200–6600 ft) 0–700 m (0–2300 ft)
Distribution
from FNA
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
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CT; DE; FL; GA; IL; IN; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WI; WV; NB; NS; PE; Ont
[WildflowerSearch map]
[BONAP county map]
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.)

Potamogeton pulcher is similar in morphology to P. amplifolius and occurs in similar habitats. Potamogeton pulcher differs from P. amplifolius by the former having lanceolate to linear-lanceolate submersed leaves with fewer than 19 veins, whereas the latter has ovate submersed leaves with more than 19 veins.

(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
P. alpinus, P. amplifolius, P. bicupulatus, P. clystocarpus, P. confervoides, P. crispus, P. diversifolius, P. epihydrus, P. floridanus, P. foliosus, P. friesii, P. gramineus, P. groenlandicus, P. hillii, P. illinoensis, P. natans, P. nodosus, P. oakesianus, P. oblongus, P. obtusifolius, P. ogdenii, P. perfoliatus, P. praelongus, P. pulcher, P. pusillus, P. richardsonii, P. robbinsii, P. spirillus, P. subsibiricus, P. tennesseensis, P. vaseyi, P. zosteriformis
P. alpinus, P. amplifolius, P. bicupulatus, P. clystocarpus, P. confervoides, P. crispus, P. diversifolius, P. epihydrus, P. floridanus, P. foliosus, P. friesii, P. gramineus, P. groenlandicus, P. hillii, P. illinoensis, P. natans, P. nodosus, P. oakesianus, P. oblongus, P. obtusifolius, P. ogdenii, P. perfoliatus, P. praelongus, P. pusillus, P. richardsonii, P. robbinsii, P. spirillus, P. strictifolius, P. subsibiricus, P. tennesseensis, P. vaseyi, P. zosteriformis
Synonyms P. strictifolius var. rutiloides
Name authority A. Bennett: J. Bot. 40: 148. (1902) Tuckerman: American Journal of Science, and Arts 45:38. (1843)
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