Myriophyllum verticillatum, the whorl-leaf watermilfoil or whorled water-milfoil, is a native to much of the North America, North Africa, and Eurasia. It closely resembles another native milfoil, called northern water milfoil (M. sibiricum) Whorled water milfoil is also easily confused with four types of invasive milfoils: Eurasian water milfoil (M. spicatum), Variable water-milfoil (M. heterophyllum), Parrot feather (M. aquaticum), and hybr (Wikipedia)