General: Perennial aquatic or semi-aquatic herb from a tuber-producing rhizome; stems 20-50 (90) cm tall.
Leaves: All basal, blades of the emergent leaves arrowhead-shaped, 5-25 cm long, long-stalked and sheathed at the base, blades of the submerged leaves lanceolate, or linear and essentially bladeless, up to 80 cm long.
Flowers: Inflorescence an open, bracteate panicle of stalked flowers, the bracts egg-shaped, rounded or hooded at the tips, 5-10 (15) mm long; mature male and female flower stalks of equal length; petals white, 1-2 cm long; sepals 5-8 mm long.
Fruits: Achenes, numerous in a globular cluster, winged, 2-3.5 mm long, sharp-beaked, the beaks extending at right angles to the body, 0.5-1.5 mm long.
Wet ditches, ponds, lakeshores and marshes in the lowland, steppe and montane zones; infrequent in BC south of 56degreeN, absent from Queen Charlotte Islands, N Vancouver Island and adjacent coast; E to PQ, NB and NS and S to ME, PA, NC, FL, MS, TX, NM, AZ and CA; N South America, HI.
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)
