Myriophyllum heterophyllum, Variable Watermilfoil


Invasive Species: Myriophyllum heterophyllum, Variable Watermilfoil

Variable watermilfoil is an invasiveĀ perennial aquatic herb that has leaves of two noticeably different forms. The submerged leaves are finely dissected, whorled, reddish/greenish-brown, and 1/2 to 2 1/2 in. (1.3 to 6.4 cm) long. The emergent leaves are small, oval, bright green, whorled, and up to 1/4 in. (0.6 cm) wide. Emergent leaves stand 6 to 8 in. (15.2 to 20.3 cm) out of the water and may not be apparent until …

Myriophyllum aquaticum, Parrotfeather Watermilfoil


Invasive Species: Myriophyllum aquaticum, Parrotfeather Watermilfoil

Parrotfeather watermilfoil is an herbaceous, rooted, submerged/emergent plant that invades aquatic habitats throughout much of the United States. Stems are stout and blue-green in color. Leaves are abundant, whorled, pinnately compound, and finely dissected. Submersed leaves are 0.6 to 1.4 in. (1.5 to 3.5 cm) long and have 20 to 30 divisions per leaf. Emergent leaves are 0.8 to 2 in. (2 to 5 cm) long, less divided, and greener than the submersed …