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

Potamogeton oakesianus J.W. Robbins
Oakes' pondweed
Potamogetonaceae (Horned pondweed family)

Introduction to Vascular Plants

© Curtis Bjork  Email the photographer   (Photo ID #25340)

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Distribution of Potamogeton oakesianus
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Species Information

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Perennial, aquatic herb from strong rhizomes; stems up to 100 cm long, branched.
Submersed leaves reduced to narrow, firm, cylindrical stalks without blades, growing from the branches of the main stem, 5-15 cm long, the stipules 2-4 cm long, delicate, shredded with age; floating leaves egg-shaped, 3-5 cm long, 1-3 cm wide, the larger ones with 9 to 19 veins, leathery, long-stalked, the tips rounded, rounded or tapering at the bases.
Inflorescence spikelike, the spikes 1.5-3 cm long, with 3 to 8 whorls of flowers, the stalks slightly inflated.
Achenes, widely egg-shaped, 2.5-3.5 mm long, 2-2.4 mm wide, the beaks cylindrical, the keels obscure, developed in the upper half of achenes.
Stem anatomical characters Interlacunar bundles strongly developed in the outer interlacunar circle of aerenchyma with some bundles scattered in the neighbouring circles, subepidermal bundles absent, pseudohypodermis absent or 1 cell thick, endodermis of U-cells.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Lakes and ponds in the lowland and montane zones; rare in SW and SC BC, known only from Steelhead (near Vancouver) and Mara Lake; disjunct E to MB, E to NF and S to ME, MA, PA, SC, TN, WI, MN and MT.

Source: The Illustrated Flora of British Columbia


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.

Taxonomic and Nomenclatural Links

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General References