OregonFlora: Potamogeton praelongus

	Potamogeton praelongus
	white-stalked pondweed, white-stemmed pondweed
Stems	terete; to 210 cm; nodal glands absent.
Leaves	submersed, sessile, attached at stem nodes, not attached to stipules; stipules 30– 81 mm, fibrous, shredding at tip; blades linear-lanceolate, 50–200 × 10–30 mm; base clasping but without basal lobes, rarely wavy; tip obtuse; veins 11–33.
Inflorescences	emersed; spikes cylindric, 34–75 mm; peduncles terminal or axillary; erect to spreading, 10–30 cm.
Fruits	sessile, obovoid; turgid, 4–5.7 × 3.2–4 mm; greenish brown, dorsally keeled, occasionally laterally keeled; beaks erect, 0.6–1 mm.

	Potamogeton praelongus
Distribution	[WildflowerSearch map] [BONAP county map]
Discussion	Neutral to alkaline waters of lakes and streams. 0–1900m. BW, Est. CA, ID; north to British Columbia, east to Newfoundland, south to Mexico; Eurasia. Native. This species hybridizes with P. alpinus, P. crispus and P. gramineus.
Source	Flora of Oregon, volume 1, page 499 Nick Otting, Richard Brainerd, Barbara Wilson
Sibling taxa	P. alpinus, P. amplifolius, P. berchtoldii, P. crispus, P. diversifolius, P. epihydrus, P. fibrillosus, P. foliosus, P. gramineus, P. illinoensis, P. natans, P. nodosus, P. pusillus, P. richardsonii, P. robbinsii, P. zosteriformis
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Potamogeton praelongus

white-stalked pondweed, white-stemmed pondweed

Stems

terete; to 210 cm; nodal glands absent.

Leaves

submersed, sessile, attached at stem nodes, not attached to stipules;

stipules 30– 81 mm, fibrous, shredding at tip;

blades linear-lanceolate, 50–200 × 10–30 mm;

base clasping but without basal lobes, rarely wavy;

tip obtuse;

veins 11–33.

Inflorescences

emersed;

spikes cylindric, 34–75 mm;

peduncles terminal or axillary; erect to spreading, 10–30 cm.

Fruits

sessile, obovoid; turgid, 4–5.7 × 3.2–4 mm; greenish brown, dorsally keeled, occasionally laterally keeled;

beaks erect, 0.6–1 mm.

Potamogeton praelongus

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Neutral to alkaline waters of lakes and streams. 0–1900m. BW, Est. CA, ID; north to British Columbia, east to Newfoundland, south to Mexico; Eurasia. Native.

This species hybridizes with P. alpinus, P. crispus and P. gramineus.

Source

Flora of Oregon, volume 1, page 499
Nick Otting, Richard Brainerd, Barbara Wilson

Sibling taxa