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

General:
Perennial, aquatic herb from fibrous roots, rooting at the nodes; stems 30-80 cm long.

Leaves:
Stem leaves threadlike, alternate, 3-40 cm long, 0.2-0.5 mm wide, the tips sharp-pointed; stipules membranous, 0.5-2 (7) cm long, fused with the leaves.

Flowers:
Inflorescence on spirally coiled, axillary stalks, the coils 5 to 30, the stalks 0.2-2.5 cm long; petals lacking; stamens 2.

Fruits:
Nut-like, egg-shaped, 1.5-2 mm long; beaks lateral, erect, 0.5-1 mm long.

Notes:
This treatment follows that of Thorne (1993) and Haynes (2000) although there is still some doubt as to whether North American R. cirrhosa is the same as the European.