Azolla filiculoides

Azolla filiculoides
Zoomed picture of Azolla filiculoides

Secure  (NatureServe)
Scientific classification
Kingdom: Plantae
Division: Pteridophyta
Class: Polypodiopsida /
 Pteridopsida (disputed)
Order: Salviniales
Family: Azollaceae
Genus: Azolla
Species: A. filiculoides
Binomial name
Azolla filiculoides
Lam.[1][2]
Synonyms[2][3]
  • Azolla arbuscula Desv.
  • Azolla caroliniana Willd.
  • Azolla japonica Franch. & Sav.
  • Azolla magellanica Willd.
  • Azolla microphylla Kaulf.
  • Azolla pinnata var. japonica (Franch. & Sav.) Franch. & Sav.
  • Azolla squamosa Molina

Azolla filiculoides (Water Fern) is a species of Azolla, native to warm temperate and tropical regions of the Americas as well as most of the old world including Asia and Australia.

It is a floating aquatic fern, with very fast growth, capable of spreading over lake surfaces to give complete coverage of the water in only a few months. Each individual plant is 1–2 cm across, green tinged pink, orange or red at the edges, branching freely, and breaking into smaller sections as it grows. It is not tolerant of cold temperatures, and in temperate regions it largely dies back in winter, surviving by means of submerged buds. Like other species of Azolla, it can fix nitrogen from the air.

Fossil records from as recent as the last interglacials are known from several locations in Europe (Hyde et al. 1978).

Cultivation

The species has been introduced to many regions of the Old World, grown for its nitrogen-fixing ability which can be utilized to enhance the growth rate of crops grown in water like rice, or by removal from lakes for use as green manure. It has become naturalized, sometimes also an invasive species, in several regions, including western Europe, southern Africa, tropical Asia, Australia (where it is considered native), and New Zealand.

Distribution

Ireland: Introduced into Clandeboye Lake, Co. Down.[4]

Gallery

References

  1. ↑ In: Encyclopédie Méthodique, Botanique 1(1): 343. 1783. "Name - Azolla Lam.". Tropicos. Saint Louis, Missouri: Missouri Botanical Garden. Retrieved February 19, 2010. Annotation: a sp. nov. reference for Azolla filiculoides
    Type Specimens HT: Azolla filiculoides
  2. 1 2 Hussner, A. (2006). "NOBANIS -- Invasive Alien Species Fact Sheet -- Azolla filiculoides" (PDF). Online Database of the North European and Baltic Network on Invasive Alien Species. Heinrich Heine University, Düsseldorf. Retrieved February 19, 2010.
  3. ↑ Tropicos
  4. ↑ Hackney, P. (Ed) 1992. Stewart & Corry's Flora of the North-east of Ireland. Third Edition. Institute of Irish Studies & The Queen's University of Belfast. ISBN 0-85389-446-9(HB)

Further reading

External links

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