Variable pondweed is extremely variable in shape and size.  However, this plant usually has dark green submersed and floating leaves present.  Stems often appear dark brown.  Submersed leaves have 3 to 7 veins that run the length of each leaf, while floating leaves have 11 to 19 veins.  Typically, the leaves have stipules, wavy edges, and tend to curl inward.  Variable pondweed hybridizes with other broad-leaf species of the pondweed family and may be especially difficult to identify.