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(Najas or Water-Nymph family)


• Medicinal / Folk-medicinal aspects: •
• Adverse effects: An occupational dermatitis in rice field workers trampling Najas growing as a weed has been documented. •
• Veterinary aspects: •

The family comprises a single genus of submerged aquatic plants formerly included in the Hydrocharitaceae. They are of cosmopolitan distribution. Several are invasive weeds, less vigorous species (for example, Najas flexilis Rostk. & W.L.E. Schmidt, the slender naiad) occasionally being used as garden pond plants. Some texts refer to the family as the Naiadaceae.

Najas L.
[syn. Naias Juss.]
Bushy Pondweed, Water Nymph, Naiad, Naiade

According to Mabberley (1997), the genus comprises about 32 species; other authorities (Flora of North America 2000) recognise 40 species. The leaf margins are usually toothed; in some species the stems are armed with prickles on the internodes and abaxially on the midveins.

Some species, including Najas graminea Delile and Najas orientalis Triest & Uotila are to be found growing as weeds in rice fields of south-eastern Asia and elsewhere (Triest & Uotila 1986, Mabberley 1997). Behl et al. (1966) noted that the prickly siliceous needles of these weeds can produce irritation followed by secondary infection of the hands and feet of rice field workers.

Najas marina L.
[syns Ittnera major C.C.Gmel., Naias gracilis Morong, Najas latifolia A.Braun, Najas major All.]
Holly-Leaved Naiad, Spiny Naiad, Greater Naiad, Sawtooth

[Information available but not yet included in database]

Najas minor All.
[syns Caulinia minor Coss. & Germ., Fluvialis minor Pers., Ittnera minor C.C.Gmel.]
Brittle Waternymph, Lesser Naiad, Minor Naiad, Slender Niad, Spinyleaf Naiad

[Information available but not yet included in database]


  • Behl PN, Captain RM, Bedi BMS, Gupta S (1966) Skin-Irritant and Sensitizing Plants Found in India. New Delhi: PN Behl [WorldCat]
  • Flora of North America Editorial Committee (2000) Flora of North America North of Mexico, Vol. 22. Oxford: Oxford University Press [WorldCat] [url]
  • Mabberley DJ (2008) Mabberley's Plant-Book. A portable dictionary of plants, their classification and uses, 3rd edn. Cambridge: Cambridge University Press [WorldCat]
  • Triest L, Uotila P (1986) Najas orientalis, a rice field weed in the Far East and introduced in Turkey. Annales Botanici Fennici 23(2): 169-171 [url]
  • [ + 2 further references not yet included in database]

Richard J. Schmidt

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