title: Najas
text: Najas, the water-nymphs or naiads, is a genus of aquatic plants. It is cosmopolitan in distribution, first described for modern science by Linnaeus in 1753.  Until 1997, it was rarely placed in the Hydrocharitaceae, and was often taken as constituting (by itself) the family Najadaceae.
  
  The APG II system, of 2003 (unchanged from the APG system, of 1998), places the genus in family Hydrocharitaceae, in the order Alismatales of the monocots.
  
  An infrageneric classification of two sections is proposed: Section Americanae and sect. Caulinia.
  
  Species
   Najas affinis Rendle - South America, Senegal, Guinea-Bissau
   Najas ancistrocarpa A.Braun ex Magnus - China, Japan, Taiwan
   Najas arguta Kunth - Cuba, Costa Rica, Panama, South America
   Najas australis Bory ex Rendle - India, Madagascar, Mauritius, KwaZulu-Natal, Seychelles
   Najas baldwinii Horn - West Africa
   Najas brevistyla Rendle - Assam
   Najas browniana Rendle - southern China, India, Taiwan, Java, Cavern Island in Northern Territory of Australia
   Najas chinensis N.Z.Wang - Primorye, China, Taiwan, Japan
   Najas conferta (A.Braun) A.Braun - Cuba, Hispaniola, Panama, Brazil
   Najas faveolata A. Br. ex Magnus
   Najas filifolia R.R.Haynes - southeastern United States (Georgia, Alabama, Florida)
   Najas flexilis (Willd.) Rostk. & W.L.E. Schmidt (1824)  - temperate Northern Hemisphere
   Najas gracillima (A.Braun ex Engelm.) Magnus - Asia, North America
   Najas graminea Delile (1813) - Africa, Asia, New Guinea, Melanesia, northern Australia; naturalized in California and parts of Europe
   Najas grossareolata L.Triest - Sri Lanka
   Najas guadalupensis (Spreng.) Magnus - North and South America, Caribbean
   Najas hagerupii Horn - Ghana, Mali
   Najas halophila L.Triest - Java, New Guinea, Queensland
   Najas heteromorpha Griff. ex Voigt - eastern India
   Najas horrida A.Braun ex Magnus - Africa, Madagascar, Sinai
   Najas indica (Willd.) Cham. (1829) - Indian Subcontinent, China, Southeast Asia, New Guinea
   Najas kurziana  Rendle - Bihar, East Timor
   Najas madagascariensis Rendle - Madagascar; naturalized in Mauritius
   Najas malesiana W.J.de Wilde - India, Bangladesh, Indochina, Malaysia, Indonesia, Philippines; naturalized in eastern Brazil
   Najas marina L. (1753) - widespread and nearly cosmopolitan
   Najas minor All. (1773) - widespread in Europe, Asia, Africa; naturalized in eastern North America
   Najas oguraensis Miki - East Asia, Himalayas (Pakistan, Nepal, northern India)
   Najas pectinata (Parl.) Magnus - Sahara
   Najas pseudogracillima L.Triest - Hong Kong
   Najas rigida Griff. - eastern India
   Najas schweinfurthii Magnus - Senegal, Cameroon, Ethiopia, Sudan, Tanzania 
   Najas tenuicaulis Miki - Honshu Island in Japan
   Najas tenuifolia R.Br. - Hong Kong, Southeast Asia, Australia
   Najas tenuis Magnus – India, Sri Lanka, Myanmar
   Najas tenuissima (A.Braun ex Magnus) Magnus - Finland, Russia, Hokkaido
   Najas testui Rendle - western + central Africa
   Najas welwitschii Rendle - tropical Africa, western India
   Najas wrightiana A.Braun - Mexico, Central America, Cuba, Bahamas, Venezuela; naturalized in Florida
  
  References
  
  External links
   Najadaceae  in L. Watson and M.J. Dallwitz (1992 onwards) [http://delta-intkey.com/angio/ The families of flowering plants] : descriptions, illustrations, identification, information retrieval. Version: 9 March 2006. http://delta-intkey.com .
  Najas japonica Nakai- Flavon's art gallery
  Najadaceae of Mongolia in FloraGREIF
  
   
  Aquatic plants
  Hydrocharitaceae genera
  Taxa named by Carl Linnaeus