Water Smartweed

Polygonum is another common aquatic plant in the Yellowstone area. It resembles and can be confused with certain Pondweeds (see the Pondweed specimen pictured in an earlier post), but the manner in which the leaf veins branch is a key differentiator. In Polygonum the veins branch off the midrib of the leaves, in Pondweeds the veins arise from the petiole.