General: Perennial, aquatic herb from strong rhizomes; stems up to 150 cm long, simple or branched.
Leaves: Submersed leaves narrowly lanceolate, flat, leathery, dark green, 4-15 cm long, 1-4 cm wide, with 7 to 15 veins, the tips blunt, tapering into long stalks greater than 2 cm long, the stipules 3-6 cm long, delicate and early decaying; floating leaves lanceolate to elliptical, 5-20 cm long, 2-7 cm wide, leathery, long-stalked, the tips pointed, tapering at the bases.
Flowers: Inflorescence spikelike, the spikes 3-6 cm long, with 10 to 16 whorls of flowers, the stalks thick, inflated.
Fruits: Achenes, widely egg-shaped or almost globe-shaped, 3.5-4 mm long, 2.5-3 mm wide, the beaks short, the keels strongly developed.
Notes: Stem anatomical characters Interlacunar and subepidermal bundles absent, pseudohypodermis absent, endodermis of O-cells with variably thickened cell walls and approaching U-cells.
Lakes and sloughs of the lowland zone; rare in the lower Fraser River Valley and in the Okanagan Valley, doubtful elsewhere; cosmopolitan with disjunctions, E to PQ and NB and S to ME, MA, PA, NC, FL, MS, TX, NM, AZ and CA; Eurasia, Mexico, S America, Africa.
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)
