Native water milfoil (Myriophyllum humile??) photographed by Maria Gross and Don Yurewicz in Dolloff Cove and South Cove.
Native Water-Milfoil (Myriophyllum sibiricum)
There are six species of native water-milfoils in New Hampshire, most of which have very similar habitats and characteristics. Native milfoil species tend to grow in small clumps or patches, and rarely grow to dominate the shallows of a waterbody. There are also two species of non-native (exotic) water-milfoil (variable milfoil and eurasian milfoil) that tend to be more invasive in their nature, and are more robust in size than the native water-milfoils ("Aquatic Plants and Algae of New Hampshire’s Lakes and Ponds")
Native milfoils have a thin red or green stem with fine leaves radiating from the main stem in whorls of 3-5 leaves per whorl, or in a more scattered radiating pattern. The leaves are typically 1 to 3 cm long and finely feather-divided, with 3 to 12 thread-like leaflet pairs per leaf. See the attached milfoil comparison chart from the Lake Stewards of Maine (click here).
Native milfoils may be confused with other plants that have finely divided leaves including bladderworts, fanwort, hornwort species, mermaid weed, water crowfoot species, water marigold, and other members of the water-milfoil genus.