E-Flora BC: Electronic Atlas of the Flora of British Columbia

Potamogeton praelongus Wulfen
long-stalked pondweed (whitestem pondweed)
Potamogetonaceae (Horned pondweed family)

Introduction to Vascular Plants

© Adolf Ceska  Email the photographer   (Photo ID #11283)

E-Flora BC Static Map
Distribution of Potamogeton praelongus
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Species Information

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Perennial, aquatic herb from strong rhizomes; stems mostly unbranched, often flexuous, nearly circular in cross-section, tapered, up to 200 cm long.
All submersed, linear-lanceolate, thin, flat, light green fading to white, 10-20 cm long, 2-4 cm wide, with 11 to 33 veins, clasping the stem, the tips rounded or hood-shaped, the stipules 3-10 cm long, fibrous or stringy; floating leaves absent.
Inflorescence spikelike, the spikes 3-5 cm long, with 6 to 12 whorls of flowers, the stalks inflated.
Achenes, widely egg-shaped or almost globe-shaped, 4.3-5.7 mm long, 3.2-4 mm wide, the beaks prominent, widely triangular, the keels wide.
Stem anatomical characters interlacunar bundles throughout the stem aerenchyma, subepidermal bundles absent, pseudohypodermis 1 to 3 cells thick, endodermis of U-cells.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Late Spring
Fruit/Seed characteristics:
Colour: Green
Present over the Summer
Source:  The USDA

Habitat / Range

Lakes in the lowland, steppe and montane zones; frequent throughout BC; circumpolar, N to AK, YT and NT, E to NF and S to ME, MA, NY, OH, IN, IL, IA, NE, CO, UT, ID and CA; Eurasia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Potamogeton praelongus

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres)
Slope Gradient (%)
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: CWH(1)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Potamogeton praelongus var. angustifolius Graebn.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References