Common duckweed  (Lemna gibba)

Common duckweed at water surface

Facts

Kingdom Plantae
Phylum Anthophyta
Class Liliopsida
Order Arales
Family Lemnaceae
Genus Lemna (1)
Size Diameter: 1.5-5 mm (2)
Root length: 15 mm (2)
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Status

Common and widespread (3).

Description

This duckweed is one of Britain's most common small water plants, which forms familiar green mats covering stagnant water bodies (4). It has a simple plant body, known as a thallus, which floats on the surface of the water and measures up to five millimetres in diameter (2). A single root hangs down into the water (2).

Range

Widespread throughout Britain, but is absent from much of Scotland and Shetland (2). Elsewhere the species has a very wide global distribution, absent only from polar areas and the tropics (2).

You can view distribution information for this species at the National Biodiversity Network GatewayDisplay NBN Map Button

Habitat

Found in a wide range of still or slow-flowing water bodies, common duckweed can also occur on mud or damp rocks (3).

Biology

This species spreads mainly through vegetative reproduction (3), but flowers are occasionally produced in shallow water exposed to the full sun (2). When covering the entire surface of a pond, it can make the water appear solid, and in parts of the north-west of England children were scared away from such ponds by the myth of Jenny Green-teeth, a pond elf or monster whose presence was indicated by duckweed; she was said to lure children into ponds and drown them (5).

Threats

Not currently threatened.

Conservation

Not relevant.

Further Information

For more information on British plants and their conservation see

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Glossary

Thallus: Type of simple plant body that does not have stems, leaves and roots.
Vegetative reproduction: Type of asexual reproduction (reproduction without recombination of genetic material) that results in the propagation of plants using only the vegetative tissues such as leaves or stems. The resulting plant is genetically identical to the original plant. A well-known example of this is the reproduction of strawberry plants from 'runners'.

References

  1. National Biodiversity Network Species Dictionary (February, 2003)
    http://www.nhm.ac.uk/nbn/
  2. Clapham, A.R., Tutin, T.G. and Moore, D.M. (1987) Flora of the British Isles. 3rd Edition. Cambridge University Press, Cambridge.
  3. Preston, C.D., Pearman, D.A. and Dines, T.D. (2002) The New Atlas of the British and Irish Flora. Oxford University Press, Oxford.
  4. Mabey, R. (1996) Flora Britannica. Sinclair-Stevenson, London.
  5. Grigson, G. (1996) The Englishman's Flora. Helicon, Oxford.