Najas spp.:Naiads, water nymphs. Najadaceae (water-nymph or naiad family).
Native and non-native annuals. Rooted in the substrate; roots emerge from seed or nodes on the stem. The long slender green stems branch frequently, grow to several feet, and extend horizontally at the surface. Leaves are opposite, sometimes in whorls, without stipules or sheaths (compare to the alternate leaf arrangement and stipules of Potamogeton spp.). The small leaves are narrow, linear, and strap-like, 0.25 - 1.5 in (0.6 - 3.75 cm) long; each blade has a widened base that clasps the stem, meeting the leaf base on the opposite side. Leaves are more or less conspicuously toothed along their margins. Leaves are green to reddish-purple; the midvein and/or underside may be more reddish than the rest of the blade. Inconspicuous, single, stalkless flowers are borne in the angle between the leaf bases and the stem; one-seeded pointed fruits are produced and seed production is usually high. These species are often a component of varied submersed plant communities.
