There are about 40 species of naiads in the world and they are all submersed plants. Southern naiad may be found in springs, fresh and brackish lakes, ponds, and canals, sometimes forming mats. Five species of Najas occur in Florida (Wunderlin, 2003). Southern naiad is widely distributed thoughout the US and parts of Canada (Kartesz, 1999).
The stems of naiad species are very long and have many branches. All naiads have very narrow, inch-long leaves that have definite teeth on their margins. Southern naiad leaves are less than 1/16 inch wide. With a hand lens, very tiny teeth can be seen along the leaf margins. Naiad leaves are arranged oppositely on the stem, or sometimes in whorls of three. The leaves are deep green to purplish-green. The flowers are very small and inconspicuous.
For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.