Hydrocotyle ranunculoides L.f.

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English Floating pennywort Status LU: absent. 1st record: n/a.
Lëtzebuergesch Grousse Waassernuebel Status Eur.: established. 1st record: NL, BE, UK 1980s. IAS of EU concern (2016)
Français Hydrocotyle fausse renoncule RA: ISEIA: A0, Alert List. Harmonia+: 0,38.
Deutsch Großer Wassernabel Wikipedia: Wikipedia - English - Floating pennywort Wikipedia - Français - Hydrocotyle fausse renoncule Wikipedia - Nederlands - Grote waternavel Wikispecies: Wikispecies - Hydrocotyle ranunculoides | CABI
Nederlands Grote waternavel Back to the list of neophytes

Report the species

Report Hydrocotyle ranunculoides to the National Museum of Natural History.

Brief description

Hydrocotyle ranunculoides L.f. is an aquatic plant that thrives in slow-flowing water bodies, particularly in ditches, canals, lakes and ponds. It prefers eutrophic waters, but it can also colonise marshes and mesotrophic water bodies. The species forms dense interwoven mats of vegetation which can quickly cover the entire water surface. Due to its vigorous growth, this plant causes loss of light and reduction in dissolved oxygen content in the water. As a consequence, the native submerged and water-edge plant species can be outcompeted, and ecosystem functions can be altered (Branquart et al. 2013).

IAS of Union concern

In 2016, Hydrocotyle ranunculoides L.f. was added to the list of invasive alien species of Union concern (Anonymous 2016) which implies that member states shall take all necessary steps to prevent it’s unintentional introduction or spread.

Status and distribution in Luxembourg

Hydrocotyle ranunculoides L.f. has not yet been observed in Luxembourg.

Risk assessment

ISEIA protocol

A0 (2+3+3+3) = Alert List (Ries et al. 2013: 18).

Harmonia+ protocol

Overall risk score 0,38 = (Overall Invasion score 0,65 x Overall Impact score 0,58) (Ries et al. 2020).


Worldwide distribution


Verloove & Heyneman (2021) have published an identification key allowing to identify the species of Hydrocotyle currently found in Belgium.


  • Anonymous, 2016. Commission implementing regulation (EU) 2016/1141 of 13 July 2016 adopting a list of invasive alien species of Union concern pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 189: 4-5.
  • Branquart, E., I. Stiers, L. Triest, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2013. Harmonia database: Hydrocotyle ranunculoides L. f.. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-11-21]
  • CABI, 2019. Hydrocotyle ranunculoides. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-03-02]
  • Ries, C., Y. Krippel & M. Pfeiffenschneider, 2020. Risk assessment after the Harmonia+ protocol of invasive alien vascular plant species in Luxembourg. Bull. Soc. Nat. luxemb. 122: 197-205. [PDF 132 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]
  • Verloove, F. & G. Heyneman, 2021. A note on some alien species of Hydrocotyle (Araliaceae) in Belgium. Dumortiera 117: 26-29. [PDF]

 Page content last updated on 2021-03-28. Last proofread by Caroline Grounds on 2019-11-18.