Water knotweed

from Wikipedia, the free encyclopedia
Water knotweed
Water knotweed (Persicaria amphibia)

Water knotweed ( Persicaria amphibia )

Systematics
Eudicotyledons
Nuclear eudicotyledons
Order : Clove-like (Caryophyllales)
Family : Knotweed family (Polygonaceae)
Genre : Knot oak ( Persicaria )
Type : Water knotweed
Scientific name
Persicaria amphibia
( L. ) Delarbre

Water knotweed ( Persicaria amphibia (L.) Delarbre ; Syn .: Polygonum amphibium L. ) is a species of the knotweed family . Depending on the location (water level), it forms water and land forms.

description

Water knotweed, landform
Water form and transitions to land form
Large population in the Elbe Valley

The water knotweed is a perennial herbaceous plant . The landform becomes about 30 to 100 cm tall; the water form can be 60 cm to 3 m (rhizome) long and has very long-stalked, oblong-elliptical leaves up to 10 cm long. The blade of the leaves has a clipped to heart-shaped base. In contrast to the bare floating leaves, the leaves of the landform have an adjacent hairiness. They are up to 20 cm long and have a short stalk. Some of them have dark spots.

The often unisexual flowers are pink in color and have no glands. Usually it forms five stamens . In addition, the individual flowers are in false ears and the individual flowers often overlap.

The species chromosome number is 2n = 90 or 66.

ecology

As an amphibious plant, the water knotweed can be grown on land, e.g. B. occur on dry roadsides, as well as in water.

The landform is a sticky, hairy, narrow-leaved stem plant with a pithy stem that rarely flowers. It is a hemicryptophyte and has attached hairy leaves. In dry locations there is no seed set, but there is intensive vegetative propagation starting from the rhizome .

The water form is Schlammwurzler with broad floating leaves and top-side stomata , the stems have m long in this case wide air corridors and to 3, arching Ascending swimming rung. In addition, the water form has a higher proportion of antibiotic substances than the land form. The water form is a hydrophyte that is anchored in the bottom of the water with a rhizome and has elongated, bare floating leaves.

The water knotweed is pollinated by insects . Often comes self-pollination before. The seeds spread through the water ( hydrochory ).

Occurrence

The water knotweed occurs in Eurasia, in North Africa and in North and South America. It is circumpolar . The plant grows mainly in stagnant water, on banks, on wet meadows and fields. In Central Europe, the water form is a nympheion association character, while the land form is a type of the societies of the Polygono-Chenopodietalia or the Agropyron-Rumicion association. In the Allgäu Alps, the species rises in the Tyrolean part on the Haldensee up to 1124 m above sea level. The species is also used as an aquarium plant ("blood red water knotweed" or "orange red water knotweed" with a dark spot in the middle of the leaf).

Systematics

The species was first described by Carl von Linné as Polygonum amphibium in 1753. Later, Antoine Delarbre (1724–1813) placed it in the genus Persicaria in 1800 and thus recombined it to Persicaria amphibia .

Danger

Since this species was still widespread in 2013, it is listed by the IUCN as Least Concern .

Combat

The water knotweed is not very sensitive to the use of herbicides . It is targeted by fruit growers with glyphosate .

literature

  • Elfrune Wendelberger: Plants of the wetlands - bodies of water, moors, floodplains. Book guild Gutenberg, Munich 1986, ISBN 3-7632-3265-6 . (or BLV-Verlag, ISBN 3-405-12967-2 )
  • Gerald Thompson, Jennifer Coldry, George Bernard: The Pond. Kosmos Verlag, Stuttgart 1986, ISBN 3-440-05670-8 .
  • Ruprecht Düll , Herfried Kutzelnigg : Pocket dictionary of plants in Germany and neighboring countries. The most common Central European species in portrait. 7th, corrected and enlarged edition. Quelle & Meyer, Wiebelsheim 2011, ISBN 978-3-494-01424-1 .

Individual evidence

  1. a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas. 8th edition. Verlag Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 , p. 336.
  2. Erhard Dörr, Wolfgang Lippert : Flora of the Allgäu and its surroundings . Volume 1, IHW-Verlag, Eching near Munich 2001, ISBN 3-930167-50-6 , p. 450.
  3. ^ Hans-Georg Kramer: Plant aquaristics á la Kramer. Tetra-Verlag, Berlin-Velten 2009, ISBN 978-3-89745-190-2 , pp. 218-221.
  4. Persicaria amphibia in the IUCN Red List of Threatened Species 2013.2. Listed by: Lansdown, RV, 2012. Retrieved May 14, 2014.
  5. ^ Weed profile: Landwasser knotweed
  6. Work diary 2014 of the fruit growing research institute Jork , p. 185.

Web links

Commons : Aquatic Knotweed ( Persicaria amphibia )  - Album with pictures, videos and audio files