Basal Leaf Structure

Look at the shape of veination pattern of a single leaf of your plant. Choose a large, clean leaf for this step. Look at the pattern of lines, or veins, in the leaf itself. If the leaf is covered by a dark film, it can be gently scraped off with a fingernail under running water.
 

Wild Celery Vallisneria americana	Sparganium species
Leaves are limp and unable to stand upright out of the water. Each leaf has two distinct vein patters, with the veins on the outside running primarily from tip to base only, and veins on the inside a slightly different color with more veins running across the leaf.	All leaves are stiff. Veins are subtle and may not be visible. Cells are uniform in size across the entire leaf.