Lemnaceae

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Image:Duckweeds.jpg Lemnaceae is a botanical name for a family of aquatic flowering plants, commonly called duckweeds. The duckweeds are monocots, members of the aroid family, the Araceae.

These plants are very simple, lacking a stem or true leaves, but consisting of a small blade-like structure (the thallus) floating on or just under the water surface, with or without primary roots. Reproduction is mostly by vegetative budding, but under appropriate environmental conditions a flowers are produced. Each flower (some call it an inflorescence) consists of two stamens and a pistil with three unisexual flowers. The fruit is an utricle, a sac containing air and a seed designed to float. The flower of Wolffia is the smallest in the world at 0.3 mm long.

Members of the Lemnaceae are found world-wide throughout the tropical and termperate zones.

Duckweeds are a significant food source for herbivorous fish and waterfowl, and they are sometimes eaten by humans in parts of Southeast Asia (as khai-nam). Some duckweeds are used in freshwater aquariums and ponds where they may spread rapidly, although in a large pond may be difficult to eradicate once established. The plants can provide nitrate removal (if cropped) and cover for fry. The plants are used as shelter by pond water species, such as bullfrogs and bluegills. The duckweeds are important in the process of bioremediation because they grow rapidly, absorbing excess mineral nutrients, particularly nitrogen and phosphates. A cover of duckweeds will reduce evaporation of water compared to a clear surface.

Image:Lemna minor3.jpg Image:LentejasDeAgua.jpg Image:Lemna minor1.jpg Image:Lemna trisulca0.jpg

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References and external links

  • Armstrong, W. (2005) Wayne Armstrong's treatment of the Lemnaceae. [1].
  • Cross, J.W. (2006). The Charms of Duckweed. [2]
  • Landolt, E. (1986) Biosystematic investigations in the family of duckweeds (Lemnaceae). Vol. 2. The family of Lemnaceae - A monographic study. Part 1 of the monograph: Morphology; karyology; ecology; geographic distribution; systematic position; nomenclature; descriptions. Veröff. Geobot. Inst., Stiftung Rübel, ETH, Zurich.
  • Watson, L. and M.J. Dallwitz (1992 onwards). Lemnaceae in The families of flowering plants: descriptions, illustrations, identification, information retrieval. http://delta-intkey.comda:Andemad-familien (Lemnaceae)

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