Hunchback duckweed

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Hunchback duckweed
Hunchback duckweed (Lemna gibba)

Hunchback duckweed ( Lemna gibba )

Systematics
Monocots
Order : Frog-spoon-like (Alismatales)
Family : Arum family (Araceae)
Subfamily : Duckweed family (Lemnoideae)
Genre : Duckweed ( Lemna )
Type : Hunchback duckweed
Scientific name
Lemna Gibba
L.

The hunchback duckweed ( Lemna gibba ) is a species from the genus of the duckweed ( Lemna ) within the family of the arum family (Araceae).

Lemna gibba in transverse profile (left) and from below (right); also note the individual root threads per branch (partly missing on the right)
Scion links bulging on the underside

description

There is no division into stem and leaf. Duckweed usually consists of one or more green "leaflets" (more precisely: phyllocladia ) that contain air-filled cavities. They swim with it on the surface of water. From these leaflets, a root sinks down into the water, with which nutrient salts can be absorbed.

The floating leaves are 3 to 5 millimeters in size and round-oval. The hunchbacked duckweed can be distinguished from the other, flatter species by the fact that the underside of its scion limbs is strongly bulbous in summer. The top is also slightly curved. In autumn, however, the branches flatten out again. It belongs to the common types of duckweed, but is often misunderstood and uncritically addressed as a small duckweed . Usually one to three (rarely six) shoot members are connected.

The number of chromosomes is 2n = 64, less often 40 or 50.

ecology

Duckweed reproduces mainly asexually by sprouting , in which the laterally growing shoots either remain connected to the mother plant or become independent. The duckweed rarely forms small, inconspicuous flowers . It stores starch in autumn and then sinks to the frost-free ground for winter.

As the water is completely covered, only little light enters the water, which prevents submerged plants from growing and, for example, also influences the water temperature. The large biomass production from branches that die in autumn contributes to the silting of the water.

Occurrence

The hunchback duckweed is found from Europe to Central Asia and Pakistan, in Africa and in America. Lemna gibba occurs on sunny, stagnant, very nutrient-rich (nitrogen-polluted) bodies of water such as ponds and cattle troughs , which it soon completely covers with its floating leaves. The hunchback duckweed forms both monospecific dominance stocks and societies with other duckweed. It is a character species of Lemnetum gibbae from the association Lemnion minoris.

literature

  • Henning Haeupler, Thomas Muer: picture atlas of the fern and flowering plants of Germany . Ed .: Federal Agency for Nature Conservation (=  The fern and flowering plants of Germany . Volume 2 ). Eugen Ulmer, Stuttgart (Hohenheim) 2000, ISBN 3-8001-3364-4 .
  • Elfrunde Wendelberger: Planting the wetlands (= BLV intensive guide ). blv, Munich 1986, ISBN 3-405-12967-2 .
  • Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , p. 327.

Individual evidence

  1. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp.  120 .
  2. ↑ Rafaël Govaerts (Ed.): Lemna gibba - data sheet at World Checklist of Selected Plant Families of the Board of Trustees of the Royal Botanic Gardens, Kew. Last accessed on August 28, 2016.

Web links

Commons : Hunchback Duckweed ( Lemna gibba )  - Collection of images, videos, and audio files