Knot pondweed

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Knot pondweed
Knot pondweed (Potamogeton nodosus), illustration

Knot pondweed ( Potamogeton nodosus ), illustration

Systematics
Class : Bedecktsamer (Magnoliopsida)
Monocots
Order : Frog-spoon-like (Alismatales)
Family : Pondweed family (Potamogetonaceae)
Genre : Spawn herbs ( Potamogeton )
Type : Knot pondweed
Scientific name
Potamogeton nodosus
Poir.

The knotted pondweed ( Potamogeton nodosus ), also called flood pondweed , is a species of the genus pondweed ( Potamogeton ) within the family of the pondweed plants (Potamogetonaceae). The name flooding pondweed is unfavorable because it is also used for Potamogeton × fluitans (= Potamogeton lucens × Potamogeton natans ), a clan with which the knotted pondweed should not be confused.

description

The knotted pondweed is an herbaceous plant . The stem is 1 to 3 meters long, has few branches and has knots that follow one another closely at the base of the stem . The elongated-elliptical, coarse floating leaves are 10 to 15 (sometimes up to 25) cm long and 4 (sometimes up to 6) cm wide, they have a fine network of nerves and lie fan-shaped on the surface of the water; the petiole is longer than the blade.

The flowering period is from June to September. However, the plant rarely flowers. The stem is slightly thickened at the top and up to 13 cm long. The ear is 2 to 5 (rarely up to 7) cm long. The flowers are about 2.5 cm wide.

The chromosome number of the species is 2n = 52.

Knot pondweed ( Potamogeton nodosus )

Occurrence

The knotted pondweed is cosmopolitan. The main area of ​​distribution is in the northern hemisphere . It includes North America (north to 50 ° north latitude), Europe , and western Asia . In Europe the common pondweed is absent in Ireland, in England it occurs only in the south, otherwise it can be found in Europe northwards to about 55 ° north latitude. In Central and South America, the knotted pondweed is rarely found, as well as in Africa (except in North Africa , where it is more common), in India and in Southeast Asia .

The knotted pondweed grows in slow or fast flowing, base-rich , meso- to eutrophic waters . In rivers, streams, ditches and lakes on gravelly and sandy , often mud - and humus-rich soil in 0.5 to 1.5, often up to 4 meters of water. It is a character species of Ranunculetum fluitantis from the association Ranunculion fluitantis, but also occurs in societies of the association Nymphaeion.

literature

  • Siegmund Seybold : The flora of Germany and the neighboring countries. A book for identifying all wild and frequently cultivated vascular plants . Founded by Otto Schmeil , Jost Fitschen . 95th completely revised and expanded edition. Quelle & Meyer, Wiebelsheim 2011, ISBN 978-3-494-01498-2 .
  • Henning Haeupler, Thomas Muer: picture atlas of the fern and flowering plants of Germany . Published by the Federal Agency for Nature Conservation (=  The fern and flowering plants of Germany . Volume 2 ). 2nd corrected and enlarged edition. Eugen Ulmer, Stuttgart (Hohenheim) 2007, ISBN 978-3-8001-4990-2 .
  • Oskar Sebald, Siegmund Seybold, Georg Philippi, Arno Wörz (eds.): The fern and flowering plants of Baden-Württemberg . tape 7 : Special part (Spermatophyta, subclasses Alismatidae, Liliidae part 1, Commelinidae part 1): Butomaceae to Poaceae . Eugen Ulmer, Stuttgart (Hohenheim) 1998, ISBN 3-8001-3316-4 , pp. 62-63 .

Individual evidence

  1. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . 8th edition. Page 106. Stuttgart, Verlag Eugen Ulmer, 2001. ISBN 3-8001-3131-5
  2. ↑ Rafaël Govaerts (ed.): Potamogeton nodosus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 16, 2016.

Web links

Commons : Nodal pondweed ( Potamogeton nodosus )  - Collection of images, videos and audio files