Najas

A-C Large Naiad ( Najas marina) D -F Small Naiad ( N. minor) H Flexible Naiad ( N. flexilis, flower)

The genus of herbs mermaids ( Najas ) is a plant genus in the subfamily Hydrilloideae, which is attributed to the family of the frog bite plants ( Hydrocharitaceae ). All species of this genus live exclusively in the water. The botanical genus name derives from the Greek water nymphs, naiads, from.

Description

All kinds of mermaids herbs are herbaceous aquatic plants from fresh or brackish water, usually annual, rarely perennial grow. The Stems are branched lean and strong, in the bottom node arise roots, the lower internodes are elongated, the upper reduced. The leaves are opposite or nearly are arranged almost quirlartig by the shortened internodes. They are sessile and divided into leaf blade and Auricula ( auricles ). The leaf blades are linear and flattened, einnervig, the leaf edges are usually cut on each side five to one hundred teeth. The Auricula are shaped differently, each includes a pair of thin, translucent sheet shed one, the edge of the auricle is sharp -toothed usually, on each side one to 15 teeth.

There are both monoecious ( monoecious getrenntgeschlechtige ) and dioecious ( dioecious getrenntgeschlechtige ) representative. The unisexual flowers are individually or in groups, sessile in the axils, each individual is usually surrounded by a membrane-like husk. A perianth is not formed. The short-stalked male flowers consist of a single stamen, the anther consists of one or four theca, the vertical jump. The stamens are at first very short, extended to anthesis but something. The sessile, female flowers consist of a single carpel with a single ovule, placentation is basal. The single pen is divided into two to four strong pointed stigma lobes.

The one-seeded fruit resembles a achene, the pericarp fits close to the seed. The seeds have no endosperm.

System

The first publication of the genus name Najas was made in 1753 by Carl Linnaeus in Species Plantarum, 1015 synonyms for Najas L. are: .. Caulinia Willd, fluvialis me. ex Adans. , Ittnera C.C.Gmel.

There are about 40 species in the genus, which occur worldwide total (selection):

  • Najas ancistrocarpa A.Br. ex Magnus
  • Najas browniana Rendle
  • Najas filifolia R.R.Haynes
  • Flexible Naiad ( Najas flexilis ( Willdenow ) Rostkovius & WLESchmidt, Syn: Najas caespitosus ( Maguire ) Reveal, Najas canadensis Michaux ), is found in Europe, Siberia and North America
  • Najas gracillima ( A.Braun ex Engelmann ) Magnus ( Syn: Najas indica var gracillima A.Braun ex Engelmann ), is found in eastern North America and is naturalized in rice fields in northern Italy
  • Najas graminea Delile ( Syn: .. Najas alagensis Poll, Najas seminuda handle), is found in South Asia, Australia, New Caledonia and in Africa, and is naturalized in rice fields in northern Italy, Romania and Bulgaria
  • Kleinzähniges Naiad or Guadeloupe Naiad ( Najas guadalupensis ( Sprengel ) Magnus ): History: Central and South America, is used as an aquarium plant; with four subspecies.
  • Indian Naiad ( Najas indica ( Willd. ) Cham. ), Occur in tropical Asia
  • Najas japonica Nakai
  • Najas Malesiana W. J. de Wilde, is found in South East Asia
  • Sea - Naiad Naiad or Large ( Najas marina L., Syn: Najas gracilis ( Morong ) Small, Najas fucoides handle, Najas major All. . ): Large Naiad Najas marina L. subsp. marina, with a cosmopolitan distribution
  • Middle Naiad ( Najas marina subsp intermedia ( Gorski ) Caspe, Syn. Najas intermedia Gorski )

Swell

  • Robert R. Haynes: Najadaceae in the Flora of North America, Volume 22: Najas - Online.
  • James Edgar Dandy: Najas L. In: Thomas Gaskell Tutin include: Flora Europaea. Volume 5, page 13-14. Cambridge University Press 1980. ISBN 0-521-20108- X
  • Walter Erhardt et al: The big walleye. Encyclopedia of plant names. Volume 2 Eugen Ulmer Verlag, Stuttgart, 2008. ISBN 978-3-8001-5406-7
Stigma (botany) Tom Tutin
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