Potamogeton

Krause's pondweed ( Potamogeton crispus )

The pondweed ( Potamogeton ) are a circumpolar spread throughout the temperate and subtropical zones of both hemispheres aquatic plant genus of the family of pondweed family ( Potamogetonaceae ). From the covered here genus of pond weeds come in Central Europe ( Germany ) about 21 species, but also at least 17 hybrids of these species before individual, which can greatly complicate the determination.

Features

It is perennial ( multi-year ), in the seabed -rooted diving or floating plants whose terminal, eared, inconspicuous greenish inflorescences emerging from the water to wind pollination. The lack perianth is replaced by four stamen appendages. The network often annoying translucent diving leaves growing generally alternate and have a sheath on. The leaf shape varies between narrow - linear and roundish. It occurs in both very tender built types as well as those with strong underwater and / or floating leaves. Some species develop up to three meters long shoots and colonize deep water zones accordingly. The best known and most common type is probably the Floating pondweed ( Potamogeton natans ), which can form large floating leaf - carpets on the aquatic environment.

Ecology, occurrence

Pondweeds are the eponymous and distinctive genus of phytosociological class of " Potamogetonetea pectinati R. Tx. & PrSG. 1942 corr. Oberd. 1979 " ( = pondweed and floating leaf companies ) and several case under various associations and dominance companies. The plants form "Underwater Forests", the numerous animals a habitat and - provide opportunities to Ei-/Laichablage and contribute to the oxygenation and self-purification of waters - as the name implies.

There are colonized different types of waters: Still waters such as ponds, pools, small ponds and diving leaf zones of large lakes, but also weakly to moderately flowing waters such as streams, rivers, canals and ditches. Some species are adapted to nutrient- poor sites; However, most prefer moderately eutrophic waters. As a result of human intervention in the landscape - among other things, water pollution, river straightening, grave clearance - many pondweed species become rare and are on the Red List of endangered plant species. Also, by the spread of neophytic anthropogenic naturalized in Europe Waterweed some pondweed stocks were displaced.

Species and hybrids ( × ) of the genus Potamogeton in Central Europe

  • Spitzblättriges pondweed - P. acutifolius Link
  • Alpine pondweed - P. alpinus Balb.
  • Narrow- leaved pondweed - P. × angustifolius J. Presl ( Hybr. from P. lucens and P. gramineus )
  • Berchtold dwarf pondweed - P. berchtoldii fever
  • Potamogeton × cognatus ( Hybr. from P. perfoliatus and P. praelongus )
  • Dyed pondweed - P. coloratus Hornem.
  • Flachstängeliges pondweed - P. compressus L.
  • Potamogeton × cooperi ( Hybr. from P. crispus and P. perfoliatus )
  • Frizzy pondweed - P. crispus L.
  • Thread - leaved pondweed - P. filiformis Pers.
  • Flood end pondweed - P. × fluitans Roth ( Hybr. from P. lucens and P. natans )
  • Stachelspitziges pondweed - P. friesii Rupr.
  • Potamogeton × gessnacensis ( Hybr. from P. natans and P. polygonifolius )
  • Grass - leaved pondweed - P. gramineus L.
  • Swiss pondweed - P. helveticus (G. Fish. ) WDJ cook
  • Potamogeton × lintonii ( Hybr. from P. crispus and P. friesii )
  • Reflecting pondweed - P. lucens L.
  • Floating pondweed - P. natans L.
  • Potamogeton × nericius ( Hybr. from P. alpinus and P. gramineus )
  • Shimmering Pondweed - P. × nitens Weber ( Hybr. from P. gramineus and P. perfoliatus )
  • Potamogeton × annoying ( Hybr. from P. alpinus and P. lucens )
  • Node - pondweed - P. nodosus Poir.
  • Stumpfblättriges pondweed - P. obtusifolius Mert. & W.D.J. cook
  • Potamogeton × olivaceus ( Hybr. from P. alpinus and P. crispus )
  • Comb pondweed - P. pectinatus L.
  • By Mature pondweed - P. perfoliatus L.
  • Knotweed pondweed - P. polygonifolius Pourr.
  • Stretched pondweed - P. praelongus Wulfen
  • Ordinary dwarf pondweed - P. pusillus L.
  • Reddish Pondweed - P. rutilus Wolfg.
  • Weidenblättriges pondweed - P. × salicifolius Wolfg. ( Hybr. from P. lucens and P. perfoliatus )
  • Potamogeton × schreberi ( Hybr. from P. natans and P. nodosus )
  • Ribs annoying pondweed - P. × sparganifolius Laest. ex Fr ( Hybr. from P. natans and P. gramineus )
  • Spateliges pondweed - P. × spathulatus Schrad. ex W.D.J. Koch & Ziz ( Hybr. from P. alpinus and P. polygonifolius )
  • Potamogeton × suecicus ( Hybr. from P. filiformis and P. pectinatus )
  • Haarblättriges pondweed - P. trichoides Cham. & Schltdl.
  • Potamogeton × undulatus ( Hybr. from P. crispus and P. praelongus )
  • Potamogeton × variifolius ( Hybr. from P. natans and P. berchtoldii )

Remarks: The taxonomic status of dwarf pondweeds Potamogeton pusillus and P. berchtoldii is not yet sufficiently clarified due to the large variability. Since both species are very difficult to tell them apart, they are also called collective species " Potamogeton pusillus agg. " Treated.

Other European species

The following European species do not occur in Central Europe:

  • Potamogeton epihydrus Rafin. , Occurs in North America, in North-West Scotland and North West England
  • Potamogeton vaginatus Turcz. , Occurs in North Asia, North America, in Eastern Sweden and western Finland
Human impact on the environment Potamogeton alpinus Stuckenia pectinata Potamogeton perfoliatus Potamogeton praelongus James Edgar Dandy Tom Tutin
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