WHORLED WATER-MILFOIL
COMB WATER-MILFOIL
Myriophyllum verticillatum
NATIVE TO MAINE
Whorled water-milfoil in-situ
Description: Whorled water-milfoil has two distinct leaf types: submersed leaves and emergent leaves (called bracts). The submersed leaves are finely a href="Glossary.php#Feathered">feather-divided
, with 5 to 14 thread-like leaflet pairs per leaf. Whorls of 4 or 5 leaves are spaced (up to 1 cm apart) along the stem. Whorled milfoil produces flowers and fruits above or at the water's surface on erect (4 to 15 cm) spikes. The bracts occurring on the emergent spike are pinnately lobed (like a double-sided comb). Even when fully developed, the flowers are very small. (A hand lens may be needed to study this feature.) The bracts are typically two or more times longer than the flowers and fruits. Toward the end of the growing season, elongated club-shaped winter buds (or turions), comprised of small stiff leaves, are formed along the submersed stems.
U.S. range map of whorled water-milfoil
U.S. Range: Whorled water-milfoil is native to Maine, new England and to other parts of the United States.
Look Alikes: The native milfoil that whorled water-milfoil most closely resembles is northern water-milfoil. Whorled milfoil may also be confused with two fo the invasive milfoils: variable water-milfoil, and Eurasian water-milfoil. Whorled water-milfoil is the closest native look alike to variable water-milfoil.
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 Water Quality Monitoring |  Aquatic Invasive Monitoring |
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