Leaves with a Midrib

Look carefully at the shape and vein pattern of your specimen and compare to each figure:
Note: there are 3 choices for this level.

Potamogeton crispus (1 of 3)   Leaves are transparent, wrinkled or "curly" with a single parallel (from tip to base of leaf) midrib and many transverse (across leaf) veins. Leaf size is highly variable.	Ludwigia species (2 of 3)   Leaves are opaque and not curly, with both transverse and parallel veins.
Potamogeton perfoliatus (3 of 3)   Leaves are transparent, relatively short (less than two inches), moderately curly with only parallel veins

If you don't think your plant is represented above try going back a level and choosing again.