Wolffia arrhiza 

Scope: Europe
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Liliopsida Alismatales Araceae

Scientific Name: Wolffia arrhiza (L.) Horkel ex Wimm.
Regional Assessments:
Common Name(s):
English Rootless Duckweed
French Wolffia sans Racines, Wollfie
Lemna arrhiza L.
Wolffia michelii Schleid.
Taxonomic Notes:

There are no significant taxonomic issues associated with this name.

Assessment Information [top]

Red List Category & Criteria: Least Concern (Regional assessment) ver 3.1
Year Published: 2011
Date Assessed: 2010-02-25
Assessor(s): Lansdown, R.V.
Reviewer(s): Kaplan, Z. & Bilz, M.
Contributor(s): Abeli, T., Bazos, I., de Bélair, G., Foggi, B., García Murillo, P.G. & Grillas, P.
European regional assessment: Least Concern (LC)
EU 27 regional assessment: Least Concern (LC)
This species is classed as Least Concern as it is widespread with stable populations and does not face any major threats.

Geographic Range [top]

Range Description:The main distribution centre for W. arrhiza is in Europe, with populations scattered throughout Africa south of the Sahara, as well as a few populations in North Africa and Asia, as well as a locality near Rio de Janeiro, Brazil (Landolt 1986).
Countries occurrence:
Albania; Austria; Belarus; Belgium; Bulgaria; Croatia; Czech Republic; France (France (mainland)); Germany; Hungary; Italy (Italy (mainland), Sicilia); Liechtenstein; Luxembourg; Moldova; Netherlands; Poland; Portugal (Portugal (mainland)); Romania; Russian Federation (Central European Russia, East European Russia); Serbia; Slovakia; Slovenia; Spain (Spain (mainland)); Switzerland; Ukraine (Ukraine (main part)); United Kingdom (Great Britain)
Additional data:
Range Map:164241-1

Population [top]

Population:W. arrhiza naturally undergoes massive population fluctuations, when it occurs at low abundance it is extremely easy to overlook. Most populations in Europe appear stable but is has declined in parts of the UK.
Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:W. arrhiza typically occurs in base-rich lowland ditches and ponds (Preston and Croft 1997) in mesotrophic to eutrophic water.

Use and Trade [top]

Use and Trade:

Threats [top]

Major Threat(s):

There are no known past, ongoing, or future threats to the survival of this species.

Conservation Actions [top]

Conservation Actions:

It is classed as Critically Endangered in the Czech Republic (Procházka 2001). There are no conservation measures in place or needed.

Citation: Lansdown, R.V. 2011. Wolffia arrhiza. The IUCN Red List of Threatened Species 2011: e.T164241A5794404. . Downloaded on 20 September 2018.
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