Perennial, aquatic herb from fibrous roots; stems compressed, branched, up to 150 cm long.
All submersed, narrowly oblong with parallel sides, 1-10 cm long, 0.4-1 cm wide, with 9 to 35 veins, attached at the nodes, the tips rounded, the bases rounded and toothed, the margins wavy, with tiny teeth, dark green and crispy, stipules inconspicuous, 0.5 cm long.
Inflorescence spikelike, the spikes 2.5-4 cm long, with 3 to 5 whorls of flowers, the stalks thin.
Achenes, lanceolate, 5-6 mm long (including the beaks), 2-2.3 mm wide, the beaks 2-3 mm long, prominent, pointed, the keels well-developed, toothed.
Stem anatomical characters Interlacunar and subepidermal bundles absent, pseudohypodermis 1 cell thick, endodermis of O-cells.
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Present from Spring to Summer
Source: The USDA