Azolla filiculoides Lam.

English Water fern ISEIA: C1
Lëtzebuergesch Waasserfar EASIN
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Deutsch Großer Algenfarn Wikispecies: Wikispecies - Azolla filiculoides
Nederlands Grote kroosvaren Back to the list of neophytes

Report the species

Report Azolla filiculoides to the National Museum of Natural History.

Importance and distribution in Luxembourg

Distribution map of Azolla filiculoides Lam. in Luxembourg. Recorder-LUX & iNaturalist, 2019.08.26.

In Luxembourg, Azolla filiculoides has so far been observed only once: On 10th July 2009 it was found in three ponds close to Bourscheid (Kesselkapp) (Krippel & Colling 2010).

Azolla filiculoides is an aquatic fern that settles in ponds, ditches, water reservoirs, wetlands, channels and slow flowing rivers, often together with Lemna minuta. It does not tolerate turbulence or fast flowing water. The plant is spread by flood waters and by the movement of birds, animals and man. It can form dense, floating and monospecific mats at the surface of water bodies that reduce light penetration and gas exchange. These mats often reduce the development of algae, other aquatic plants and animals. However, dense populations seem to be transient and well localized (Sources:

Risk assessment

ISEIA protocol: C1 (2+2+2+2) (Ries et al. 2013: 18).

Bibliography concerning Luxembourg

  • Krippel, Y. & G. Colling, 2010. Notes floristiques. Observations faites au Luxembourg (2008- 2009). Bull. Soc. Nat. luxemb. 111: 11-32. [PDF 209 KB]
  • Ries, C., Y. Krippel, M. Pfeiffenschneider & S. Schneider, 2013. Environmental impact assessment and black, watch and alert list classification after the ISEIA Protocol of non-native vascular plant species in Luxembourg. Bull. Soc. Nat. luxemb. 114: 15-21. [PDF 652 KB]

Suggested citation of this webpage

Ries, C. & M. Pfeiffenschneider (Eds.), 2019. Azolla filiculoides Lam. In: - Invasive Alien Species in Luxembourg. URL: [26.08.2019].

 Last updated on Monday, April 9, 2018.