Rough horn leaf

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Rough horn leaf
Rough horn leaf (Ceratophyllum demersum)

Rough horn leaf ( Ceratophyllum demersum )

Systematics
Subdivision : Seed plants (Spermatophytina)
Class : Bedecktsamer (Magnoliopsida)
Order : Horn leaf-like (Ceratophyllales)
Family : Horn leaf family (Ceratophyllaceae)
Genre : Horn leaf ( Ceratophyllum )
Type : Rough horn leaf
Scientific name
Ceratophyllum demersum
L.
illustration
Male flowers

The rough horn leaf ( Ceratophyllum demersum ), also called the common horn leaf , is a submerged ("demers") aquatic plant (hydrophyte) from the horn leaf family (Ceratophyllaceae).

distribution and habitat

The rough horn leaf is widespread in nutrient-rich stagnant or slowly flowing waters throughout Germany, Europe, northern Asia and North America. It usually grows over humus mud soils in water depths of 0.5 to 10 meters.

Locations and occurrences in Central Europe

The rough horn leaf needs nutrient-rich, warm, stagnant water with a pronounced muddy bottom.

It occurs in lakes and backwaters, especially in bays that are sheltered from the wind, mainly in areas from 0.5 to 1 m deep. In Central Europe it is a character species of the order Potamogetonetalia and occurs particularly in the Myriophyllo-Nupharetum, the Nymphoidetum and the Trapetum.

In Central Europe it occurs in the lowlands and in the low mountain ranges; it only rises occasionally up to about 900 m. In the Alps , too , it is only found sporadically in the warmer areas. In Central Europe it is missing in larger areas.

General distribution

The rough horn leaf occurs worldwide - with the exception of the Arctic and the Antarctic .

In Europe , its distribution area extends northwards to Iceland and the Faroe Islands , in Scandinavia it occurs up to latitude 69 ° north.

description

The rough horn leaf is a submerged, free-floating or anchored in the ground with colorless sprouts without roots. The often reddish stems are between 30 and 100 centimeters long. The leaves are dark green, rigid and fragile. They are forked once or twice and have two to four narrow, sharp-toothed tips. There are four to twelve leaves in a whorl .

The inconspicuous, sexually separated flowers stand individually in the leaf whorls. The male flowers stand below the female ones. They are about 3 millimeters long and have eight to 24 stamens and 9 to 15 narrow bracts . The female flowers have only one ovary . The ripe, black and egg-shaped fruits are drawn out in two at the base and in one thorn at the top. The fruits are rarely winged. The rest of the style is as long as or longer than the fruit. The plant rarely blooms, then between July and September.

The number of chromosomes is 2n = 24.

ecology

The rough horn leaf is a submerged, floating or "stuck", up to 3 m long water plant . It shows the following typical hydromorphic adaptations: the absence of roots (instead there are parts of the shoots with root character), no stomata; a central vascular bundle provides tensile strength; Tannin cells serve to protect against rot; there are ventilation ducts. Propagation is primarily vegetatively through shattering shoot pieces, and descending through the winter, rising in the spring by gas production, starchy winter buds , called Turionen . These occur at low temperatures through growth inhibition of the internodes . Sexual reproduction only plays a subordinate role. The rough horn leaf is an underwater bloomer. The pollen-rich, monoecious flowers press out the 10–12 stamens with the help of a pressure mechanism on the perigone . While the above air-containing dust bag float, fall provided with a balloon-like attachment pollen grains that have a specific gravity of 1.0, out and pass through the water movement to the long scars of female flowers. There is the case of water pollination. Flowering time is from June to September.

The fruits are also dispersed with water currents. The small 1-seeded nuts are also typical Velcro fruits, with their stylus remnants and 2 basal spines serving as Velcro organs. Therefore, the spread by water birds, which carry the fruits in the plumage to other waters, also plays a role. A body of water can often only be repopulated in this way.

Systematics

One can distinguish between three varieties and one shape:

  • Ceratophyllum demersum var. Apiculatum (Cham.) Asch. : It occurs in Europe, tropical Africa, India and America.
  • Ceratophyllum demersum var. Demersum : It is cosmopolitan.
  • Ceratophyllum demersum var. Inerme J.Gay ex Radcl.-Sm. : It occurs in Germany, France, Iraq and Ghana.
  • Ceratophyllum demersum f. missionis (Wall. ex Wight & Arn.) Wilmot-Dear : It occurs in Europe, in tropical Asia and in tropical northeastern Africa.

literature

  • E. Oberdorfer: Plant-sociological excursion flora . Ulmer, Stuttgart 1994, ISBN 3-8252-1828-7 .
  • Henning Haeupler , Thomas Muer: picture atlas of the fern and flowering plants of Germany (= the fern and flowering plants of Germany. Volume 2). Published by the Federal Agency for Nature Conservation. Ulmer, Stuttgart 2000, ISBN 3-8001-3364-4 .
  • H. Bellmann: Life in brook and pond - plants and invertebrates of small water bodies . Orbis, Munich 2000, ISBN 3-572-01085-3 .
  • 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 .
  • Dietmar Aichele, Heinz-Werner Schwegler: The flowering plants of Central Europe , Franckh-Kosmos-Verlag, 2nd revised edition 1994, 2000, Volume 2, ISBN 3-440-08048-X
  • Oskar Sebald, Siegmund Seybold, Georg Philippi (Hrsg.): The fern and flowering plants of Baden-Württemberg. Volume 1: General Part, Special Part (Pteridophyta, Spermatophyta): Lycopodiaceae to Plumbaginaceae. 2nd, supplemented edition. Eugen Ulmer, Stuttgart 1993, ISBN 3-8001-3322-9 .
  • Christel Kasselmann : aquarium plants . Ulmer Verlag, Stuttgart 1995; 2nd edition 1999, ISBN 3-8001-7454-5 , p. 164 f. and 447.

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 . Page 392.
  2. ↑ a b c d e Rafaël Govaerts (Ed.): Ceratophyllum - World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew. Last accessed on January 26, 2017.

Web links

Commons : Raues Hornblatt  - Album with pictures, videos and audio files

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