Naiad - Najas marina
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Najas marina is submersed with brittle stems up to about 0.5 m long that
are often branched toward the upward portion of the plant. The internodes
of the stem usually have conspicuous, brownish, prickly teeth. The leaves
are opposite or sometimes in whorls of three, 0.5 to 4.0 cm long, and
have triangular teeth along the leaf margins and prickles along the midrib
on the underside of the leaf. Plants are dioecious with the male and female
flowers borne on separate individuals. The flowers are solitary in the
leaf axils. The female flowers produce ovoid seeds 2.0 to 4.5 mm long
that have 3 to 4-angled areolae that are irregularly arranged.
Spiny naiad is found in brackish or highly alkaline ponds, lakes, and
coastal and inland marshes. Plants are reported to reproduce by seed and
fragmentation (Tarver et al. 1986). Studies by Vierssen (1982) have shown
seed germination of N. marina to be best in decomposing organic matter,
at 24° C under dark conditions. Agami and Waisel (1986) found the
germination of N. marina to be increased after passing through the digestive
tract of mallard ducks and postulate that ducks may be a major factor
in long range dispersal of N. marina.
Najas marina can sometimes interfere with boating and fishing. However,
the plant is considered to be an excellent waterfowl food (Tarver et al.
Links to more information
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For more information on this plant or management please contact US Army Corp of Engineers