Habitat: naiad is found in the submersed plant community, growing in ponds, lakes, and slow moving streams in depths up to 5 meters. Preferring sand and gravel, the plants thrive in a wide range of substrates. naiad is tolerant of turbidity and eutrophic (nutrient rich, productive) conditions.
Description: Unlike most aquatic plants, naiad is a true annual. Seedlings grow from slender roots, developing stems up to 2.5 meters long that often branch profusely near the top. The leaf arrangement is not strict, and leaves may appear to be opposite, sub-opposite, in whorls or clumps. The leaves are small (rarely more than 3.5 cm long) and very slender (0.3 – 0.5mm wide), strapshaped, pointed and serrated. Unlike all native naiads whose leaf serrations or spines are virtually invisible to the unaided eye, the leaf serrations of naiad, though tiny, can usually be observed without magnification. Visible serrations, therefore, provide a key characteristic for identifying this invader. A second characteristic that distinguishes naiad from two of Maine’s three native naiad species— including the most common by far, Najasflexilis—is the abruptly protruding (as opposed to gently flaring) blocky or fanshaped leaf base. The upper margin of the leaf base is finely toothed or fringed in appearance. You may need to carefully pull the leaf away from the stem and use a hand lens to see the base clearly. (Note: The leaf base of a third native species, Najasgracillima, is also blocky and toothed, however the occurrence of this species in Maine is rare.) Like all naiads, the flowers are small, inconspicuous, and borne in the leaf axils. The seeds are purplish, 1.5 to 3.0 mm long, spindle shaped and slightly curved, with rectangular indentations arranged in distinct longitudinal rows. |
