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

Potamogeton pusillus L.
small pondweed
Potamogetonaceae (Horned pondweed family)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #65749)

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

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Perennial, aquatic herb from fine, tufted roots; stems up to 100 cm long, sparingly branched.
All submersed, linear, the sides parallel, thin, green, 1-15 cm long, 0.3-3 cm wide, unstalked, usually with 3 veins, the tips pointed, the stipules 0.5-1 cm long, delicate, not fibrous, greenish or brownish, the margins fused, the veins obscure and faint, the basal glands at nodes well-developed.
Inflorescence spikelike, the spikes 0.5-1.5 cm long, with 2 to 5 whorls of flowers, the stalks thin; bases of the winter buds soft, smooth.
Achenes, almost rounded, 1.5-2.8 mm long, 1.6-2 mm wide, widest above the middle, the beaks short, stubby, the keels absent.
Two subspecies, occasionally treated as separate species (e.g., Douglas et al 1994) can be distinguished in our area.

1. Stipules with fused margins; leaves without translucent bands along the midveins or with the bands up to 2-rows wide on each side of the midveins; marginal veins join the midveins about 2 mm from the leaf tips in a sharp angle....................ssp. pusillus

1. Stipules with overlapping margins; leaves with translucent bands up to 5-rows wide on each side of the midveins; marginal veins join the midveins about 0.5-1 mm from the leaf tips in a blunt (60 degree) angle....................ssp. tenuissimus (Mert. & Koch) Haynes & C.B. Hellquist

Source: The Illustrated Flora of British Columbia

Habitat / Range

Lakes, ponds, sloughs and ditches in the lowland, steppe and montane zones; frequent in BC; circumpolar, N to AK, YT and NT, E to NF and S to ME, MA, PA, NC, FL, MS, LA, TX, NM, AZ and CA; Eurasia, Mexico, Africa.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Potamogeton pusillus

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) 1050 1083 1117
Slope Gradient (%) 0 0 0
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
8 8 8
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: SBPS(2)


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 berchtoldii Fieber
Potamogeton berchtoldii var. acuminatus Fieber
Potamogeton berchtoldii var. colpophilus (Fernald) Fernald
Potamogeton berchtoldii var. lacunatus (Hagstr.) Fernald
Potamogeton berchtoldii var. mucronatus Fieber
Potamogeton berchtoldii var. polyphyllus (Morong) Fernald
Potamogeton berchtoldii var. tenuissimus (Mert. & W.D.J. Koch) Fernald
Potamogeton gemmiparus (J.W. Robbins) J.W. Robbins ex Morong
Potamogeton pusillus subsp. groenlandicus (Hagstr.) Bocher
Potamogeton pusillus var. gemmiparus J.W. Robbins
Potamogeton pusillus var. mucronatus (Fieber) Graebn.
Potamogeton pusillus var. tenuissimus Mert. & W.D.J. Koch

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References