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

General:
Perennial, aquatic herb from fine, tufted roots; stems up to 100 cm long, sparingly branched.

Leaves:
All submersed, linear, the sides parallel, thin, green, 1-15 cm long, 0.3-3 cm wide, unstalked, usually with 3 veins, the tips pointed, the stipules 0.5-1 cm long, delicate, not fibrous, greenish or brownish, the margins fused, the veins obscure and faint, the basal glands at nodes well-developed.

Flowers:
Inflorescence spikelike, the spikes 0.5-1.5 cm long, with 2 to 5 whorls of flowers, the stalks thin; bases of the winter buds soft, smooth.

Fruits:
Achenes, almost rounded, 1.5-2.8 mm long, 1.6-2 mm wide, widest above the middle, the beaks short, stubby, the keels absent.

Notes:
Two subspecies, occasionally treated as separate species (e.g., Douglas et al 1994) can be distinguished in our area.

1. Stipules with fused margins; leaves without translucent bands along the midveins or with the bands up to 2-rows wide on each side of the midveins; marginal veins join the midveins about 2 mm from the leaf tips in a sharp angle....................ssp. pusillus

1. Stipules with overlapping margins; leaves with translucent bands up to 5-rows wide on each side of the midveins; marginal veins join the midveins about 0.5-1 mm from the leaf tips in a blunt (60 degree) angle....................ssp. tenuissimus (Mert. & Koch) Haynes & C.B. Hellquist