Mermaid herbs

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Mermaid herbs
Illustration of Najas species: A – C Large mermaid (Najas marina) D – F Small mermaid (Najas minor) H Flexible mermaid (Najas flexilis, flower)

Illustration of Najas species: A – C Large mermaid ( Najas marina )
D – F Small mermaid ( Najas minor )
H Flexible mermaid ( Najas flexilis , flower)

Class : Bedecktsamer (Magnoliopsida)
Order : Frog-spoon-like (Alismatales)
Family : Frog bite family (Hydrocharitaceae)
Subfamily : Hydrilloideae
Genre : Mermaid herbs
Scientific name

The genus of mermaid herbs ( Najas ) is a genus of plants within the frog-bite family (Hydrocharitaceae). All species of this genus live exclusively in water. Up to 40 species are distributed almost worldwide.


Illustration of the great mermaid ( Najas marina )

All species of mermaid grow as aquatic plants in fresh or brackish water . They are usually annual, rarely herbaceous plants . The shoot axes are slender and strongly branched, roots develop in the lower nodes, the lower internodes are elongated, the upper internodes are reduced. The leaves are almost opposite to one another or, due to the shortened internodes, are arranged almost like a whorl . They are sessile and subdivided into leaf blades and auricles (auricles). The leaf blades are linear and flattened, single-nerved, the leaf margins are usually serrated, five to a hundred teeth on each side. The auricles are shaped differently, each including a pair of thin, translucent leaf scales, the edge of the auricle is usually pointed-toothed, one to 15 teeth on each side.

There are both monoecious (single-sexually separated) and dioecious (dioecious separate-sexed) species. The unisexual flowers stand individually or in groups in the armpits, each one is usually surrounded by a membrane- like bract . An inflorescence is not formed. The short-stalked male flowers consist of a single stamen , the anthers of which consist of one or four theca that pop open vertically. The stamens are initially very short, but lengthen somewhat to the anthesis . The sessile, female flowers consist of a single carpel with only one ovule , the placentation is basal. The single stylus is in two to four strongly pointed stigma lobes divided.

The solitary fruit resembles an achene , the pericarp is close to the seed . The seeds have no endosperm .

Systematics and distribution

Najas gracillima with diaspores
Guadeloupe mermaid ( Najas guadalupensis )
Great mermaid ( Najas marina )

The genus name Najas was first published in 1753 by Carl von Linné in Species Plantarum , 2, p. 1015. The botanical genus name Najas is derived from the Greek water nymphs , naiads . Synonyms for Najas L. are: Caulinia Willd. , Fluvialis Me. ex Adans. , Fluvialis Ség ., Ittnera C.C. Gmel .

The genus Najas belongs to the subfamily Hydrilloideae within the family Hydrocharitaceae and was previously in a separate family Najadaceae Juss. ( Nixkrautgewächse ) posed.

There are up to 40 species in the genus Najas that occur all over the world:

  • Najas affinis Rendle : It is common in tropical West Africa and tropical South America.
  • Najas ancistrocarpa A.Braun ex Magnus : It is common on the Japanese island of Honshu , in Taiwan and in the southern Chinese provinces of Fujian , Hubei , Jiangxi and Zhejiang .
  • Najas arguta Kunth : It iswidespreadfrom Central to South America and in Cuba .
  • Najas australis Bory ex Rendle : It iswidespreadfrom India and the western Indian Ocean to KwaZulu-Natal .
  • Najas baldwinii Horn (Syn .: Najas liberiensis Horn ): It iswidespreadin tropical West Africa as far as Chad.
  • Najas brevistyla Rendle : It only occurs in Assam .
  • Najas browniana Rendle : It iswidespreadin India, Taiwan and Java to northern Australia and in the southeast Chinese provinces of Guangdong and Guangxi .
  • Najas chinensis N.Z.Wang : It is widespread in the Primorye region of Russia, Japan , Korea , Taiwan and the Chinese provinces of Fujian , Guangdong , Guangxi , Hainan , Hubei , Jiangxi , Jilin , Liaoning , Yunnan and Zhejiang .
  • Najas conferta (A.Braun) A.Braun : Itspreadsfrom Panama to Brazil and occurs in Cuba and Hispaniola .
  • Najas filifolia R.R. Haynes : Itspreadsfrom Georgia to Florida .
  • Flexible Naiad ( Najas flexilis (Willd.) Rostk. & WLESchmidt , Syn .: Najas canadensis Michx. , Najas flexilis var. Microcarpa Nilsson , Najas flexilis var. Robusta Morong , Najas flexilis var. Congesta Farw. , Najas flexilis subsp. Caespitosus Maguire , Najas caespitosus (Maguire) Reveal ): It thrives in temperate areas of the northern hemisphere and is widespread in Europe , Siberia and North America .
  • Najas gracillima (A.Braun ex Engelm.) Magnus (Syn .: Najas indica var. Gracillima A.Braun ex Engelmann , Najas tenuissima subsp. Amurensis (Tzvelev) Vorosch. , Najas japonica Nakai ): It is from eastern Iran to Russia's far East and temperate East Asia andwidespreadfrom eastern Canada to the north-central and eastern USA. It is a neophyte in rice fields in northern Italy.
  • Grassy mermaid ( Najas graminea Delile , Syn .: Najas graminea var. Delilei Magnus nom. Inval.): It comes from South and East Asia, Australia, New Caledonia and Africa and is a neophyte in rice fields in northern Italy, Romania and Bulgaria.
  • Najas grossareolata L.Triest ; it occurs only in Sri Lanka .
  • Small-toothed mermaid or Guadeloupe mermaid ( Najas guadalupensis (Spreng.) Magnus , Syn .: Najas flexilis var. Guadalupensis (Spreng.) A. Braun , Najas microdon A. Braun nom. Superfl.): It is from southern Canada with four subspecies widespread across the north-central, north-east and southeastern USA, central to South America and on the Caribbean islands. It is used as an aquarium plant.
  • Najas hagerupii horn : It is widespread in tropical West Africa.
  • Najas halophila L. Trieste : It occurs from Java to Queensland .
  • Najas heteromorpha handle. ex Voigt : It occurs in India.
  • Najas horrida A. Braun ex Magnus : It is distributed from Africa to the Sinai Peninsula .
  • Indian mermaid ( Najas indica (Willd.) Cham. , Syn .: Najas minor var. Indica (Cham.) A. Braun , Najas palustris Blanco , Najas lobata Blanco , Najas falciculata A. Braun , Najas tenuis Magnus , Najas foveolata A. Braun ex Rendle , Najas kingii Rendle , Najas lacerata Rendle ): distributed in tropical and subtropical Asia.
  • Najas kurziana Rendle : It only occurs in Bihar, Indiaand East Timor .
  • Najas madagascariensis Rendle : It occurs in Madagascar .
  • Najas malesiana Wilde (Syn .: Najas graminea var. Angustifolia Rendle , Najas graminea var. Minor Rendle ): It iswidespreadfrom eastern India through Southeast Asia to Malesia .
  • Large mermaid ( Najas marina L. , Syn .: Najas marina var. Genuina K.Schum. Nom. Inval.): There are four subspecies and four varieties:
    • Najas marina subsp. arsenariensis (Maire) L.Triest (Syn .: Najas arsenariensis Maire ): It occurs only in Algeria .
    • Najas marina var. Brachycarpa Trautv. (Syn .: Najas marina subsp. Brachycarpa (Trautv.) Tzvelev , Najas intramongolica Ma ): It is widespread from Central Asia to northern China.
    • Najas marina subsp. commersonii L.Triest : The distribution area is in the western Indian ocean area.
    • Najas marina var. Grossidentata Rendle : It is distributed from northeastern China to Korea.
    • Middle mermaid ( Najas marina var. Intermedia (Wolfg. Ex Gorski) Rendle , Syn .: Najas intermedia Wolfg. Ex Gorski , Najas major var. Intermedia (Wolfg. Ex Gorski) A. Braun , Najas major subsp. Intermedia (Wolfg. Ex Gorski) K. Richt. , Najas marina subsp. Intermedia (Wolfg. Ex Gorski) Casper , Najas muricata Delile nom. Illeg., Najas marina var. Muricata K.Schum. Nom. Illeg., Najas delilei Rouy , Najas armata H. Lindb. Nom. Superfl., Najas marina subsp. Armata Horn , Najas marina var. Delilei (Rouy) Maire , Najas marina subsp. Delilei (Rouy) Reekmans ): It is widespread from the Mediterranean to Yunnan and southern Africa.
    • Large mermaid ( Najas marina L. subsp. Marina , Syn .: Najas maritima Pall. , Najas major All. , Najas fluviatilis Poir. , Najas muricata Thuill. , Najas major var. Laevis DC. , Najas monosperma Willd. , Najas tetrasperma Willd . , Najas fucoides Griff. , Najas latifolia A.Braun , Najas major var. Angustifolia A.Braun , Najas major var. Ehrenbergii A.Braun , Najas major var. Microcarpa A.Braun , Najas major var. Multidentata A.Braun , Najas major var. paucidentata A. Braun , Najas marina var. muricata Hartm. , Najas marina var. angustifolia (A. Braun) A. Braun ex K.Schum. , Najas major var. gracilis Morong , Najas marina var. gracilis (Morong) Dudley , Najas marina var. Recurvata Dudley , Najas microcarpa (A.Braun) Bolle ex Christ , Najas major subsp. Multidentata (A.Braun) K.Richt. , Najas major subsp. Paucidentata (A.Braun) K.Richt. , Najas latior F.Muell. Ex K.Schum. Nom. Inval., Najas marina var. Angustissima K.Schum. , Najas marina var. Bollei K.Schum. , Najas marina var. Ehrenberg ii (A.Braun) K.Schum. , Najas marina var. Latifolia K.Schum. , Najas marina var. Latior K.Schum. , Najas marina var. Multidentata (A.Braun) K.Schum. , Najas marina var. Paucidentata K.Schum. , Najas marina var. Riedelii K.Schum. , Najas polonica Zalewski , Najas marina var. Brevifolia Rendle , Najas marina var. Californica Rendle , Najas marina var. Mexicana Rendle , Najas marina var. Denticulata Rendle , Najas gracilis (Morong) Small , Najas laevis Lojac. , Najas major var. Polonica (Zalewski) Tzvelev , Najas marina subsp. aculeolata Tzvelev , Najas marina subsp. major (All.) Viinikka , Najas marina subsp. ehrenbergii (A.Braun) L. Triest , Najas marina subsp. microcarpa (A.Braun) L.Triest , Najas marina var. kashmirensis L.Triest , Najas marina subsp. latior (K.Schum.) L. Trieste , Najas marina var. ohwii L. Trieste , Najas marina subsp. susiana L. Triest ): It is distributed almost worldwide.
    • Najas marina subsp. sumatrana (WJde Wilde) L.Triest (Syn .: Najas marina var. sumatrana Wilde ): It occurs only in western Sumatra .
    • Najas marina var. Zollingeri Rendle : It only occurs in Lake Batur in Bali .
  • Small mermaid ( Najas minor All. , Syn .: Najas subulata Thuill. , Najas fragilis (Willd.) Delile , Najas dichotoma Roxb. , Najas ternata Roxb. Ex Griff. , Najas minor var. Intermedia Ces. , Najas minor var. Spinosa Rendle , Najas minor var. Longifolia R.Corti , Najas moshanensis N.Z.Wang ): It is widespread in temperate to subtropical Eurasia and North Africa.
  • Najas oguraensis Miki : It is distributed from Pakistan to East Asia.
  • Najas pectinata (Parl.) Magnus : It is distributed from Algeria and Senegal to Egypt and the Sinai Peninsula.
  • Najas pseudogracillima L. Trieste : It only occurs in Hong Kong .
  • Najas rigida handle. : It occurs in India.
  • Najas schweinfurthii Magnus : It is distributed in Senegal , Cameroon , Ethiopia , Sudan and Tanzania .
  • Najas tenuicaulis Miki : It only occurs on the Japanese island of Honshu.
  • Najas tenuifolia R.Br. (incl. Najas pseudograminea W.Koch ): Itspreadsfrom Thailand to Australia and occurs in Hong Kong.
  • Najas tenuissima (A.Braun ex Magnus) Magnus (Syn .: Najas minor var. Tenuissima A.Braun ex Magnus , Najas minor subsp. Tenuissima (A.Braun ex Magnus) K. Richt. , Najas yezoensis Miyabe ): She is from southern Finland spread over northwestern European Russia, Russia's Far East to the Japanese island of Hokkaidō .
  • Najas testui Rendle : It is widespread in tropical Africa.
  • Najas welwitschii Rendle : They arewidespreadfrom Senegal to Angola , from Sudan and Ethiopia to Tanzania and in India.
  • Najas wrightiana A.Braun : It is distributed from Mexico to Venezuela and occurs in the Bahamas and Cuba.


Some species of mermaid have found their way into the aquarium hobby.


Individual evidence

  1. ^ W. Alan Wentz, Robert R. Haynes: Najadaceae . In: Robert E. Woodson, Jr., Robert W. Schery: Flora of Panama , Part II, Family 3b, In: Annals of the Missouri Botanical Garden , Volume 60, Number 1, 1973, pp. 1-5.
  2. ^ Najas at Missouri Botanical Garden, St. Louis, accessed August 22, 2014.
  3. a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq Rafaël Govaerts (Ed.) : Najas. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 25, 2014.
  4. ^ Najas in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved August 22, 2014.
  5. a b c d Wang Qingfeng, Robert R. Haynes & C. Barre Hellquist: Hydrocharitaceae. : Najas , S, 92 - online with the same text as the printed work , In: Wu Zheng-yi, Peter H. Raven & Deyuan Hong (eds.): Flora of China. Acoraceae-Cyperaceae. Volume 23, Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, September 2, 2010, ISBN 978-1-930723-99-3 .
  6. a b c d e f Walter Erhardt , Erich Götz, Nils Bödeker, Siegmund Seybold: The great pikeperch. Encyclopedia of Plant Names. Volume 2. Types and varieties. Eugen Ulmer, Stuttgart (Hohenheim) 2008, ISBN 978-3-8001-5406-7 .
  7. a b c James Edgar Dandy : Najas L. In: Thomas Gaskell Tutin u. a .: Flora Europaea . Volume 5, pages 13-14. Cambridge University Press 1980. ISBN 0-521-20108-X
  8. Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , pp. 366–369.

Web links

Commons : Mermaid Herbs ( Najas )  - Collection of images, videos and audio files