Stuckenia

Stuckenia is a small genus recently segregated from Potamogeton.

1. Fruit 2.2–3 mm long, beakless (with merely a wart-like apex, the broad stigma sessile); leaves rounded, ± blunt, or obtuse, often with a tiny notch, at the tip [30–40×].

S. filiformis

1. Fruit (2.5–) 3–4.5 mm long, not including a tiny beak (the short style persistent as a beak toward one side of end of fruit) leaves mostly sharp-pointed (the younger ones tapering slenderly to a point; older ones often more abruptly pointed).

S. pectinata