General:
Perennial, aquatic herb from long rhizomes; stems up to 120 cm long, 1-3 mm wide, unbranched or sparsely branched.

Leaves:
All submersed, linear, thread-like, 5-10 cm long, the lower ones up to 3 mm wide, with 1 vein, the tips round to blunt or notched, firm, dark green, the stipules 2-5 cm long, fused into inflated sheaths, the leaf blades arising close to the tips of the sheaths.

Flowers:
Inflorescence spikelike, the spikes 1.5-7 cm long, interrupted, with 3 to 12 whorls of flowers, the stalks thin.

Fruits:
Achenes, almost globe-shaped, 3.5-4 mm long, 2.5-3 mm wide, widest above the middle, the beaks and keels absent, the surface with fine, ray-like grooves.

Notes:
Many specimens in herbaria identified as Stuckenia vaginata (Potamogeton vaginatus) are, in fact, misidentified specimens of Stuckenia filiformis ssp. occidentalis.

Source:  The Illustrated Flora of British Columbia

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration Source:  The Illustrated Flora of British Columbia

Synonyms and Alternate Names:
Coleogeton vaginatus (Turcz.) D.H. Les & Haynes
Potamogeton interruptus Kit.
Potamogeton vaginatus Turcz.
Stuckenia vaginatus (Turcz.) Holub