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

General:
Perennial, aquatic herb from slender rhizomes; stems threadlike, freely branching, 20-50 cm long.

Leaves:
Stem leaves opposite, threadlike, 1-nerved, 2-10 cm long, less than 1 mm wide, the tips abruptly pointed, membranous-sheathing at the base.

Flowers:
Inflorescence of male and female flowers in the axils, sometimes not together; the female flowers mostly of 3-5 carpels, unstalked or short stalked with a subtending bract shorter than the pistils; male flowers a single stamen.

Fruits:
Achenes, stalked, the backs curved, the fronts smooth or sharply toothed, beaked, the beaks 1 mm long.