Stems flattened, little branched. Submersed leaves linear, 5–20 cm × 2–8 mm; stipules 8–20 mm long, not sheathing, deciduous. Floating leaves petiolate; blades elliptic, 2–6 cm long. Spikes 15–40 mm long, continuous. Tepals green, 1–3 mm long. Fruits 2–4 mm long, strongly keeled with a minute beak (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).