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

General:
Aquatic or semi-aquatic perennial rooting in the mud; stems slender, 5-20 cm long, submerged, partially floating or stranded on mud, leaf bases joined by small, winged ridges.

Leaves:
All opposite; submerged leaves linear, 5-20 mm long, thin, single-nerved, narrowly margined, terminally notched, veins thickened but not protruding; floating and emergent leaves broadly spoon-shaped, 3-nerved.

Flowers:
Inflorescence of tiny, conspicuous flowers borne with bracts; female flowers stalkless or shortly-stalked; styles ascending.

Fruits:
Achene-like, 4, each 1-seeded, slightly wing-margined above, with regular vertical lines of small pitlike markings. vol2_5