Blunt-leaved pondweed

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Blunt-leaved pondweed
Blunt-leaved pondweed (Potamogeton obtusifolius)

Blunt-leaved pondweed ( Potamogeton obtusifolius )

Systematics
Class : Bedecktsamer (Magnoliopsida)
Monocots
Order : Frog-spoon-like (Alismatales)
Family : Pondweed family (Potamogetonaceae)
Genre : Spawn herbs ( Potamogeton )
Type : Blunt-leaved pondweed
Scientific name
Potamogeton obtusifolius
Mert. & WDJKoch

The blunt-leaved pondweed ( Potamogeton obtusifolius ) is a species of the genus pondweed ( Potamogeton ) within the family of the pondweed plants (Potamogetonaceae). This aquatic plant is widespread in the northern hemisphere .

description

illustration

The blunt-leaved pondweed is a perennial herbaceous plant that reaches heights of 30 to 50 centimeters. It has a creeping, about 1 mm thick, strongly branched rhizome . The stem is compressed, blunt-edged and heavily branched in the upper half. The leaves are narrow, 2 to 3.5 millimeters wide, dull, pale green to reddish, barely transparent and provided with a middle nerve and two to rarely four indistinct lateral nerves. The upper ones have an oil sheen, are equipped with an air mesh and thus float on the surface of the water. The ligule are open and curled up.

The bloom time of the blunt-leaved pondweed extends from June to August. The inflorescence stem is as long as the ear. Six to eight flowers are close together in the approximately 1 centimeter long, spike-shaped inflorescence . The three-fold flowers are about 1.5 millimeters wide.

The fruits are 3.5 millimeters long and 2 millimeters wide, they are sharply keeled on the back, the fruit beak is wide and very short.

The turions are spindle-shaped, up to 4 cm long and about 5 millimeters wide, they are still present during the flowering period.

The chromosome number of the species is 2n = 26.

Occurrence

The blunt-leaved pondweed is widespread worldwide and occurs mainly in the northern hemisphere . In Europe, its distribution area extends in the south from northern Spain over the Massif Central along the northern edge of the Alps to Macedonia and Bulgaria . In the north to about 70 ° north latitude. It is becoming increasingly rare in Eastern Europe .

The blunt-leaved pondweed thrives best in base-rich , only moderately nitrogenous , somewhat acidic, lime-poor waters with muddy, humus-rich soils . It occurs in raised bog , in ponds and in meadow moors ; it is less common in ditches. It is a character species of the Potamogetonion association.

In Central Europe it occurs scattered in the lowlands , but is also absent in larger areas; it is rarely found in the low mountain ranges , in the foothills of the Alps and in Lower Austria and is also absent there in large areas; it occurs only sporadically in the Swiss Jura .

Since the blunt-leaved pondweed prefers weakly acidic waters, it naturally has only a few locations that suit it - although it tolerates low levels of nitrate. Despite its slight tolerance to nitrate , it lost around half of its previously known locations in the 20th century.

literature

  • Otto Schmeil , Jost Fitschen (greeting), Siegmund Seybold: The flora of Germany and the neighboring countries. A book for identifying all wild and frequently cultivated vascular plants. 95th completely revised u. exp. Edition. Quelle & Meyer, Wiebelsheim 2011, ISBN 978-3-494-01498-2 .
  • Rothmaler : Excursion flora from Germany, vascular plants: basic volume. 20th edition, 2011, Spektrum Verlag Heidelberg, ISBN 978-3-8274-1606-3
  • Henning Haeupler , Thomas Muer: picture atlas of the fern and flowering plants of Germany (= the fern and flowering plants of Germany. Volume 2). 2nd, corrected and enlarged edition. Published by the Federal Agency for Nature Conservation. Ulmer, Stuttgart 2007, ISBN 978-3-8001-4990-2 .
  • Oskar Sebald, Siegmund Seybold, Georg Philippi, Arno Wörz (eds.): The fern and flowering plants of Baden-Württemberg. Volume 7: Special part (Spermatophyta, subclasses Alismatidae, Liliidae Part 1, Commelinidae Part 1): Butomaceae to Poaceae. Eugen Ulmer, Stuttgart 1998, ISBN 3-8001-3316-4 .
  • Dietmar Aichele, Heinz-Werner Schwegler: The flowering plants of Central Europe. Franckh-Kosmos-Verlag, 2nd revised edition 1994, 2000, Volume 5, ISBN 3-440-08048-X

Individual evidence

  1. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . 8th edition. Page 103. Stuttgart, Verlag Eugen Ulmer, 2001. ISBN 3-8001-3131-5
  2. ↑ Rafaël Govaerts (ed.): Potamogeton obtusifolius. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Accessed June 1, 2020.

Web links

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