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Project Name Data (Last Modified On 5/9/2013)

Flora Data (Last Modified On 5/9/2013)
Description Plants herbaceous, annual or rarely perennial, aquatic, submersed in fresh or brackish waters, monoecious or dioecious. Stems slender, much branched, rooting at the lower nodes; lower internodes elongate, the upper internodes reduced. Leaves subopposite or appearing whorled because of reduced internode length, sessile, each divided into lamina and auricle; laminas linear and flattened, 1- nerved, the margins usually serrulate; auricles variously shaped, each enclosing a pair of tiny hyaline scales, the auricle margins usually spiny-toothed. Flowers axillary, sessile, solitary or clustered, each usually enclosed in a membranous involucre, the perianth absent; staminate flowers each consisting of a single stamen, the anthers 1- or 4-thecate, dehiscing vertically, the filaments at first short, elongating slightly at anthesis; carpellate flowers each consisting of a single l-ovuled carpel, the placentation basal, the styles solitary, each divided into 2-4 subulate stigmatic lobes. Fruit achene-like, the pericarp closely enveloping the seed, areolate; seeds without endosperm, areolate.
Habit herb
Distribution A monogeneric family of probably fewer than 40 species, widespread in both hemispheres
Note two species, Najas arguta H.B.K. and N. guadalupensis (Spreng.) Magnus are known to occur in Panama.4 Najas is very important as a food source for many vertebrates and as a breeding area for fishes and invertebrates. In tropical and subtropical areas, members of the genus often clog canals and water- ways. The fruits of the Najadaceae have traditionally been considered to be achenes or nutlets. However, Najas fruits can not correctly be referred to either of these fruit types since both are, by definition, "dry fruits." Najas fruits are similar to achenes in all respects except that, in the natural state, the fruits seldom remain viable when dry. We have therefore designated the fruits as "achene-like" until a better name is proposed for fruits of this type.
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