Parrot’s-feather	Status LU: established. 1st record: LU & ITW ~1990.
	Brasilien-Dausendblat	Status Eur.: established. 1st record: unkn. IAS of EU concern (2016).
	Myriophylle du Brésil	RA: ISEIA: B1, Watch List. Harmonia+: 0,51.
	Brasilianisches Tausendblatt	Wikipedia: | Wikispecies: | CABI
	Parelvederkruid	Back to the list of neophytes

Brief description

Myriophyllum aquaticum (Vell.) Verdc. is an invasive submerged/emergent aquatic weed characteristic of sub-tropical to warm-temperate regions, but found as far north as the UK. The species thrives in well-lit ponds, ditches, canals and slow-running streams. It is most often found in eutrophic water bodies and is able to grow as a terrestrial plant when ponds dry out, making it well-adapted to medium water level fluctuations (Branquart et al. 2013).

IAS of Union concern

In 2016, Myriophyllum aquaticum (Vell.) Verdc. 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

Myriophyllum aquaticum (Vell.) Verdc. was first documented by Roland Proess in his Herbarium in June 2000 at Freschewisen near Roeser, a dead branch stream of the Alzette river. According to Proess, this large population in a pond has existed for at least 10 years (Colling & Krippel 2003: 16). Parrot’s-feather’s first record for Luxembourg can thus approximately be dated to ~1990. Another observation by Mikka Mootz on 1 April 2019 in a nearby pond in Houwisen confirms the presence of the species in the same area.

In 2019, extensive patches were discovered in the Thilleweier pond in a forest environment (Dudelange). A third site was detected in 2020 near Saeul (Krippel et al. 2020: 42).

This eastern North American species is very rare, subspontaneous or naturalised [in the Luxembourg environment]. In Europe, only female flowers have been reported, which are necessarily sterile in the absence of male flowers. Apparently, however, the plants observed in the wild are only known in the vegetative state. This species became naturalised here during the 1990s. Its expansion seems to be continuing (Lambinon & Verloove 2012: 422-423).

Risk assessment

ISEIA protocol

B1 (2+2+3+3) = Watch List (Ries et al. 2013: 18).

Harmonia+ protocol

0,68Invasion
0,75Impact
0,51Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/34939#toDistributionMaps

Bibliography

• 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., L. Triest, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2013. Harmonia database: Myriophyllum aquaticum (Vell.) Verdc. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-14]
• CABI, 2019. Myriophyllum aquaticum. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-03-02]
• Colling, G. & Y. Krippel, 2003. Notes floristiques. Observations faites au Luxembourg (2000-2001). Bull. Soc. Nat. luxemb. 103: 3-23. [PDF 342 KB]
• Krippel, Y., T. Helminger & G. Colling, 2020. Notes floristiques. Observations faites au Luxembourg (2018-2019). Bulletin Soc. Nat. luxemb. 122 : 29-55. [PDF 132 KB]
• Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
• MNHNL, 2000-. Myriophyllum aquaticum (Vell.) Verdc. in Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. Musée national d’histoire naturelle, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-14]
• MNHNL, iNaturalist & GBIF, 2020. Myriophyllum aquaticum (Vell.) Verdc. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-14]
• Oly, M., 2022. Kartierung invasiver gebietsfremder Wasserpflanzen im Großherzotum Luxemburg, Untersuchungen zur Verbreitung von invasiven gebietsfremden Wasserpflanzen in einer beispielhaften Auswahl an Stillgewässern, Musée national d’histoire naturelle, Luxembourg. 117 pp. 
• Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• 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]

 Page content last updated on 2023-08-18. Last proofread by Caroline Grounds on 2019-11-20.

	Various-leaved water-milfoil	Status LU: absent. 1st record: n/a.
	Verschiddebliederegt Dausendblat	Status Eur.: established. 1st record: DE 1960s.1 IAS of EU concern (2017).
	Myriophylle hétérophylle	RA: ISEIA: B0, Alert List. Harmonia+: 0,47.
	Verschiedenblättriges Tausendblatt	Wikipedia: | Wikispecies: | CABI
	Ongelijkbladig vederkruid	Back to the list of neophytes

Brief description

Myriophyllum heterophyllum Michx. grows in well-lit ponds, ditches, canals and slow-running streams. It is found growing under a wide range of chemical conditions, but tends to prefer acidic waters. Variable watermilfoil is able produce very dense populations and high biomass. It is highly competitive and may lead to the exclusion of other submerged water plants. The dense mats it produces reduce sunlight and can restrict water movement; when decomposing, they alter water quality and reduce available oxygen. The low oxygen conditions can kill fish and harm other aquatic organisms. The plant can also cause boating and swimming hazards (Baus et al. 2013).

IAS of Union concern

In 2017, Myriophyllum heterophyllum Michx. was added to the list of invasive alien species of Union concern (Anonymous 2017) which implies that member states shall take all necessary steps to prevent it’s unintentional introduction or spread.

Status and distribution in Luxembourg

Myriophyllum heterophyllum Michx. has not yet been observed in Luxembourg (MNHNL, iNaturalist & GBIF 2020).

Risk assessment

ISEIA protocol

B0 (2+3+2+3) = Alert List (Ries et al. 2013: 18).

Harmonia+ protocol

0,63Invasion
0,75Impact
0,47Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/34940#toDistributionMaps

Bibliography

• Anonymous, 2017. Commission implementing regulation (EU) 2017/1263 of 12 July 2017 updating the list of invasive alien species of Union concern established by Implementing Regulation (EU) 2016/1141 pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 182: 37-39 (13.7.2017).
• Baus E., Branquart, E., I. Stiers, L. Triest, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2013. Harmonia database: Myriophyllum heterophyllum Michx.. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-11-21]
• CABI, 2021. Myriophyllum heterophyllum. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2021-03-04]
• MNHNL, iNaturalist & GBIF, 2020. Myriophyllum heterophyllum in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [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]

 Page content last updated on 2021-09-03. Last proofread by Caroline Grounds on 2019-11-20.

1. Cf. CABI 2021.[↩]

	Narrow-leaved ragwort	Status LU: established. 1st record: LU & ITW 1988.
	Schmuelt Kräizkräitchen	Status Eur.: established. 1st record: DE 1889.1
	Séneçon du Cap	RA: ISEIA: B2, Watch List. Harmonia+: 0,29.
	Schmalblättriges Greiskraut	Wikipedia: | Wikispecies: | CABI
	Bezemkruiskruid	Back to the list of neophytes

Brief description

Kristian Peters @ Wikimedia Commons

As a plant of the southern hemisphere, it tends to flower particularly in autumn (springtime in its region of origin) and it is only the first serious frosts that make its beautiful light-yellow flower heads disappear, carried on stems lined with linear leaves (Reichling 1990: 67).

Status and distribution in Luxembourg

Senecio inaequidens DC. was first observed in Luxembourg in the wild by Ed Melchior on 1988-07-31 on a slag heap in Differdange (Reichling 1990: 67; MNHNL 2000-). This record was published with the following annotations by Léopold Reichling: “A South African species, new to our country. It has become naturalised in some regions of southern and western Europe, closer to home, particularly in Belgium (especially the Liège region) (e.g. Van Rompaey & Delvosalle, 1979, map 1040: Delvosalle & al. 1979 and in the NW of Germany (e. g. Kuhbier, 1977). Given the momentum with which it often invades newly conquered lands, it can be expected to spread to the slag heaps and quarry bottoms of the Mining Basin. As a plant of the southern hemisphere, it tends to flower mainly in the autumn (springtime in its native land) and it is only the first serious frosts that make its beautiful light-yellow flower heads disappear, carried on stems lined with linear leaves with an embracing base” (Reichling 1990: 67; see here for the cited references).

In 2008 and 2009, isolated plants were observed in the northern part of Luxembourg (Esch/Sûre, Harlange). In 2012, only 14 observations were documented in the Recorder-Lux database (MNHNL 2000-). In 2014 a survey of the species along highways increased the number of records (Frankenberg & Gräser 2014). Currently, 164 records are accessible through the MNHNL-mdata portal (MNHNL, iNaturalist & GBIF 2021).

But while the first populations of the plant were documented in industrial areas in the south of Luxembourg, it took the species only a few years to spread to Luxembourg City as well as to the German and Belgian borders, using the motorway network as a dispersal route. A study from 2014 showed that by then the species had populated almost the entire motorway network of Luxembourg (Frankenberg & Gräser 2014).

The species is already widespread in the south of the country, mainly along the main roads, but it is also expanding in the central and northern parts of the country and is increasingly being observed at stations far from any roadside (Krippel et al. 2020: 47).

The species appeared spontaneously in 2020 and 2021 at various locations along the course of the water pipe as well as in August 2021 in the construction site of the new treatment plant of the Syndicat des eaux du barrage d’Esch-sur-Sûre (SEBES) (Wolff & Krippel 2022: 7).

The species continues to expand its range and will probably have negative impacts on biodiversity as soon as it spreads from motorways and roads into grassland, pastures and rock ecosystems.

This species, native to South Africa, is naturalised in southern and western Europe. Common to rare, with strong expansion in the wild. Roadsides, railway ballast, wastelands, slag heaps, quarry screes, lawns. Originally, this species was mainly naturalised in the eastern Mosan area (Vesdre valley and Meuse valley around Liège) and in the surroundings of Calais. It then spread (especially from the 1980s onwards), often proving to be a very invasive weed. It is now found in a large part of the region, where it is still growing (Lambinon & Verloove 2012: 739).

Risk assessment

ISEIA protocol

B2 (3+2+2+3) = Watch List (Ries et al. 2013: 19).

Harmonia+ protocol

0,76Invasion
0,38Impact
0,29Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/49557#toDistributionMaps

Bibliography

• Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2010. Harmonia database: Senecio inaequidens DC. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-15]
• CABI, 2019. Senecio inaequidens. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-03-04]
• Colling, G. et L. Reichling, 1996. Notes floristiques 1994-1995. Bull. Soc. Nat. luxemb. 97: 25-38. [PDF 596 KB]
• Colling , G. & Y. Krippel, 2001. Notes floristiques. Observations faites au Luxembourg (1998-1999). Bull. Soc. Nat. luxemb. 101: 33-48. [PDF 331 Kb]
• Frankenberg, T. & P. Gräser, 2014. Vorkommen des Schmalblättrigen Greiskrauts (Senecio inaequidens DC.) in Luxemburg, Erfassung der aktuellen Verbreitung der Art entlang der Autobahnen und Autobahnzubringer. Unveröff. Studie des Büros EFOR-ERSA im Auftrag Nationalmuseums für Naturgeschichte, Oktober 2014. 6 S. + Anhang [PDF-Bericht, PDF-Übersichtskarte].
• Krippel, Y. & G. Colling, 2008. Notes floristiques. Observations faites au Luxembourg (2006-2007). Bull. Soc. Nat. luxemb. 109: 59-76. [PDF 549 KB]
• Krippel, Y. & G. Colling, 2010. Notes floristiques. Observations faites au Luxembourg (2008- 2009). Bull. Soc. Nat. luxemb. 111: 11-32. [PDF 209 KB]
• Krippel, Y. & G. Colling, 2012. Notes floristiques. Observations faites au Luxembourg (2010-2011). Bull. Soc. Nat. luxemb. 113: 67-82. [PDF 579 KB]
• Krippel, Y. & G. Colling, 2014. Notes floristiques. Observations faites au Luxembourg (2012-2013). Bull. Soc. Nat. luxemb. 115: 109-124. [PDF 893 KB]
• Krippel, Y., T. Helminger & G. Colling, 2020. Notes floristiques. Observations faites au Luxembourg (2018-2019). Bulletin Soc. Nat. luxemb. 122 : 29-55. [PDF 132 KB]
• Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
• MNHNL, 2000-. Senecio inaequidens DC. in Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. Musée national d’histoire naturelle, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-15]
• MNHNL, iNaturalist & GBIF, 2021. Senecio inaequidens DC. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-15]
• Reichling, L., 1990. Observations floristiques au Luxembourg 1980-1989. Bull. Soc. Nat. luxemb. 90: 55-70. [PDF 808 KB]
• Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• 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]
• Wolff, J.-P. & Y. Krippel, 2022. Epilobium brachycarpum C. Presl (Onagraceae), une nouvelle espèce pour la flore du Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 124 : 3-8. [PDF 5,13 MB]

 Page content last updated on 2022-02-22. Last proofread by Caroline Grounds on 2019-11-21.

1. Cf. CABI 2019.[↩]

	Canadian waterweed, pondweed	Status LU: established. 1st record: LU & ITW ~1875
	Kanadesch Waasserpescht	Status Eur.: established. 1st record: IE 1836.
	Élodée du Canada	RA: ISEIA: A3 – Black List. Harmonia+: 0,46
	Kanadische Wasserpest	Wikipedia: | Wikispecies: | CABI
	Brede waterpest	Back to the list of neophytes

Brief description

Elodea canadensis Michx. is an aquatic plant native to North America that thrives in a variety of freshwater habitats, from still to slow-flowing systems and from very shallow to deep waters. It is most frequent in clear, nutrient-rich and alkaline waters. Elodea aggressively invaded the waterways of Europe in the 19th Century (Branquart et al. 2010).

Status and distribution in Luxembourg

Elodea canadensis Michx. was introduced around 1875 to the Grand Duchy of Luxembourg in 2 ponds between Itzig, Contern and Scheidhof (Fischer 1882: 122). In the following years, it was found in Imbringen (1883), Meysembourg (1886), Schrassig (1902), Diekirch (1906), Birelergrund (1908) and Bissen (1909). Sunnen (1918: 10) mentions the Canadian pondweed in Brasseur’s pond, located on the Outer Ring of Luxembourg’s Old Town.

The Canadian waterweed has become quite common in our regions and can be observed in both standing and river waters (Diederich 1984: 38).

The oldest herbarium specimen in the Museum was collected in 1883 by Jean Feltgen (1833-1904) in standing water in the meadows of Imbringen (Specimen № 629a MNHNL 2000-).

Until 1909 the species had not been observed in the Ardennes (Oesling) (Robert 1910: 15).

By now the Canadian waterweed is widely spread throughout the country (MNHNL, iNaturalist & GBIF 2019).

The North American plant Elodea canadensis was introduced to Europe around 1835 and quickly invaded the fresh waters of much of the continent. However, this expansion seems to have stopped or even reversed today, and is tending to be replaced by Elodea nuttallii (Planch.) H. St. John (Lambinon & Verloove 2012: 790, 791).

Risk assessment

ISEIA protocol

A3 (3+3+3+3) = Black List (Ries et al. 2013: 18).

Harmonia+ protocol

0,77Invasion
0,60Impact
0,46Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/20759#toDistributionMaps

Bibliography

• Branquart, E., I. Stiers, L. Triest, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum, F. Verloove, 2010. Harmonia database: Elodea canadensis Michx.. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-09]
• CABI, 2019. Elodea canadensis. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-02-28]
• Diederich, P., 1984. Les monocotylédones aquatiques (excl. Potamogeton s.l.) du Grand-Duché de Luxembourg. Dumortiera 29-30: 34-41. [PDF 5 MB].
• Fischer, M.-E., 1882. Plantes phanérogames nouvelles ou rares de la flore luxembourgeoise. Recueil des mémoires et des travaux publiés par la Société de botanique du grand-duché de Luxembourg 6-8: 116-124.
• Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
• MNHNL, 2000-. Elodea canadensis Michx. in Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. Musée national d’histoire naturelle, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-09-05]
• MNHNL, iNaturalist & GBIF, 2019. Elodea canadensis Michx. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-09-06]
• Oly, M., 2022. Kartierung invasiver gebietsfremder Wasserpflanzen im Großherzotum Luxemburg, Untersuchungen zur Verbreitung von invasiven gebietsfremden Wasserpflanzen in einer beispielhaften Auswahl an Stillgewässern, Musée national d’histoire naturelle, Luxembourg. 117 pp. 
• Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• 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]
• Robert, J., 1910. Beiträge zur Flora des Grossherzogtums Luxemburg. lnst. G.-D. Lux., Sect. Sc. natur., phvs., math., Arch. trimestr. n.s. V: 1-35. Luxembourg: Imprimerie de la Cour Victor-Buck.
• Sunnen, M., 1918. Die Stechmückenplage in Luxemburg und Umgebung. P. Worré-Mertens, Luxembourg, 24 p. [PDF 80 MB]

 Page content last updated on 2023-08-17. Last proofread by Caroline Grounds on 2019-11-14.

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

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

0,65Invasion
0,58Impact
0,38Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/28068#toDistributionMaps

Ressources

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

Bibliography

• 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.

	Monkeyflower	Status LU: established. 1st record: LU & ITW 1998.
	Getëppelt Mimekraut	Status Eur.: established. 1st record: unkn.
	Mimule tacheté	RA: ISEIA: C1. Harmonia+: 0,16.
	Gelbe Gauklerblume	Wikipedia: | Wikispecies: | CABI
	Gele maskerbloem	Back to the list of neophytes

Brief description

Mimulus guttatus DC. (Syn.:  Erythranthe guttata (Fisch. DC.) G.L.Nesom) typically grows in disturbed areas around river banks and is rarely found in the adjacent marshes and wet meadows. This plant species colonises gaps within the established vegetation. It can form large patches where tree cover is low and vegetation is dominated by light-demanding, ruderal and small-sized plant species, especially in the upper reaches of streams (Baus et al. 2010).

Status and distribution in Luxembourg

The western North American Mimulus guttatus DC. was first documented in Luxembourg by Gérard Schmid on 1998-09-01 near the mill on the right bank of the river Attert in the municipality of Useldange (Colling & Krippel 2001: 42).

In 2019, about 15 plants were discovered near Reimberg in the ruts left by the construction machines of a water pipeline (Krippel et al. 2020: 41).

A large population was found on 10th July 2020 around an artificial garden pond in Simmerschmelz. According to the garden owner, the species was not planted, it suddenly appeared several years ago.

Population of Mimulus guttatus around a pond in Simmerschmelz. Photo: 10 July 2020 by C. Ries.

15 records are accessible through the MNHNL-mdata portal (MNHNL, iNaturalist & GBIF 2020).

Rare to very rare, naturalised; expanding, at least locally, in the wild. Sometimes cultivated for ornamental purposes along watercourses (Lambinon & Verloove 2012: 634).

Risk assessment

ISEIA protocol

C1 (1+2+1+1) (Ries et al. 2013: 18).

Harmonia+ protocol

0,71Invasion
0,23Impact
0,16Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/115609#toDistributionMaps

Bibliography

• Baus, E., E. Branquart, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove 2010. Harmonia database: Mimulus guttatus DC.. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-14]
• CABI, 2019. Mimulus guttatus. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-03-02]
• Colling , G. & Y. Krippel, 2001. Notes floristiques. Observations faites au Luxembourg (1998-1999). Bull. Soc. Nat. luxemb. 101: 33-48. [PDF 331 Kb]
• Krippel, Y., T. Helminger & G. Colling, 2020. Notes floristiques. Observations faites au Luxembourg (2018-2019). Bulletin Soc. Nat. luxemb. 122 : 29-55. [PDF 132 KB]
• Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
• MNHNL, 2000-. Mimulus guttatus DC. in Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. Musée national d’histoire naturelle, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-14]
• MNHNL, iNaturalist & GBIF, 2020. Mimulus guttatus DC. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-07-20]
• Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• 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]

 Page content last updated on 2021-03-04. Last proofread by Caroline Grounds on 2019-11-20.

	Coneflower	Status LU: established. 1st record: LU & ITW 1887.
	Spléckbliedrege Sonnenhutt	Status Eur.: established. 1st record: <1625.1
	Rudbéckie laciniée	RA: ISEIA: C1. Harmonia+: 0,17.
	Schlitzblättriger Sonnenhut	Wikipedia: | Wikispecies: | CABI
	Slipbladige rudbeckia	Back to the list of neophytes

Brief description

Rudbeckia laciniata L. mostly grows in open ruderal and alluvial habitats (e.g. river banks). Seeds may only germinate from bare soil; the low germination and recruitment rates in undisturbed sites reduce plant capacity to colonise natural plant communities. The plant can however form dense and monospecific stands due to vegetative growth (rhizomes). R. laciniata, or coneflower, locally decreases plant species richness and hinders colonisation of open habitats by tree species, especially in riparian areas. The plant is toxic for livestock but also very melliferous (Branquart et al. 2010).

Status and distribution in Luxembourg

Rudbeckia laciniata L. was first mentioned for Luxembourg in the wild in the surroundings of Mersch by Feltgen (1901: 254).

The oldest herbarium specimen of Rudbeckia laciniata L. at the MNHNL was collected on 20 August 1935 by Jos. Witry in gardens in Schifflange (Specimen № 50794, MNHNL 2000-). The next scientific record that we know of was made by Léopold Reichling (1921-2009) on 12th June 1961 near the river Alzette in the municipality of Walferdange (MNHNL 2000-).

Currently, 2 records of coneflower are accessible through the MNHNL-mdata portal (MNHNL, iNaturalist & GBIF 2019).

This melliferous species from North America is naturalised in Europe, especially in central Europe. River and canal banks, river gravel, sometimes wasteland. Sometimes subspontaneous or adventitious. Sometimes cultivated for garden ornament (Lambinon & Verloove 2012: 719).

The species is comparable to Helianthus tuberosus in its ecology but is much less common in Luxembourg.

Risk assessment

ISEIA protocol

C1 (2+2+2+2) (Ries et al. 2013: 19).

Harmonia+ protocol

0,51Invasion
0,33Impact
0,17Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/48032#toDistributionMaps

Bibliography

• Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2010. Harmonia database: Rudbeckia laciniata L.. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-15]
• CABI, 2019. Rudbeckia laciniata. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-03-02]
• Feltgen, E., 1901. Mersch sowie nächste und weitere Umgebung, zum Gebrauch für Naturfreunde. Bulletin de la Société des naturalistes luxembourgeois 11: 246-277.
• Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
• MNHNL, 2000-. Rudbeckia laciniata L. in Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. Musée national d’histoire naturelle, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-15]
• MNHNL, iNaturalist & GBIF, 2019. Rudbeckia laciniata L. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-10-15]
• Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• 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]

 Page content last updated on 2021-03-11. Last proofread by Caroline Grounds on 2019-11-21.

1. Cf. CABI 2019.[↩]

	Spring beauty	Status LU: casual. 1st record: LU & ITW 1988.
	Wanter-Portulak	Status Eur.: established.
	Claytone de Cuba	RA: ISEIA: C1. Harmonia+: 0,04
	Gewöhnliches Tellerkraut, Winterportulak	Wikipedia: | Wikispecies:
	Winterpostelein	Back to the list of neophytes

Brief description

Claytonia perfoliata — Flora Batava, 1872

Status and distribution in Luxembourg

The oldest specimen in the herbarium of the Museum dates from 1866 and was collected in the Brussels district Uccle, Belgium, but it mentions no exact date nor a collectors name (Specimen № 2515, MNHNL 2000-).

In Luxembourg, Claytonia perfoliata Donn ex Willd. was first observed by Paul Diederich in the spring of 1988 en masse in a nursery on the plateau south-east of Lorentzweiler (LUREF 79436 E / 83775 N¹). At the same time, a few individuals were found under a tree planted in front of building n°17 on Avenue Guillaume in Luxembourg City (Reichling 1990: 58). In spring 1989, the plant was observed by Jean-Marie Mangen in an ornamental plantation at Geessekneppchen in Luxembourg City (Reichling 1990: 59). In Summer 1989, it was next observed by Kariger: 1989-06-25 on flower beds of the grounds around the City Theatre on Limpertsberg, Luxembourg City, as weed in a plant association belonging to the Digitario-Setarienion; 1989-06-10 also as a weed in flower pots at the Finsterthal campsite (Kariger 1990: 76).

On May 16, 2004, Yves Krippel and Tania Wambach observed the species growing on a surface of ± 10 m² in the woods and in a lawn on the edge of the mini-golf of the camping Maartboesch in Berdorf (Krippel et al. 2006).

Currently, 10 records of the species in Luxembourg are accessible through the MNHNL-mdata portal (MNHNL, iNaturalist & GBIF 2021).

Once grown in gardens as a vegetable plant (Lambinon & Verloove 2012: 149).

Risk assessment

ISEIA protocol

C1 (1+1+1+1) (Ries et al. 2013: 18).

Harmonia+ protocol

0,46Invasion
0,08Impact
0,04Risk

Bibliography

• Kariger, J.-J., 1990. Auf der Suche nach Seltenheiten und verschwundenem 1970-1989. Bericht und Auswahl floristischer Tätigkeit ergänzt durch ökologische Betrachtungen. Bulletin de la Société des naturalistes luxembourgeois 90: 71-101.
• Krippel, Y. & G. Colling, 2006. Notes floristiques. Observations faites au Luxembourg (2004-2005). Bull. Soc. Nat. luxemb. 107: 89-103. [PDF 288 Kb]
• Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
• MNHNL, 2000-. Claytonia perfoliata Donn ex Willd. in Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. Musée national d’histoire naturelle, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2019-09-05]
• MNHNL, iNaturalist & GBIF, 2019. Claytonia perfoliata Donn ex Willd. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2021-01-12]
• Reichling, L., 1990. Observations floristiques au Luxembourg 1980-1989. Bull. Soc. Nat. luxemb. 90: 55-70. [PDF 808 KB]
• Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• 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]
• Wikipedia contributors, 2019. Claytonia perfoliata Donn ex Willd. in Wikipedia, The Free Encyclopedia, 24 September 2019. URL: https://en.wikipedia.org/w/index.php?title=Claytonia_perfoliata&oldid=917517303 [accessed 2 October 2019]

 Page content last updated on 2021-03-02. Last proofread by Caroline Grounds on 2019-11-14.

1. Source: Diederich, P.,  2019. Personal communication by email to C. Ries on 2019-10-28.[↩]

	New Zealand pigmyweed	Status LU: established. 1st record: LU & ITW 2020.
	Weier-Nolkraut	Status Eur.: established. 1st record: UK 1911.
	Crassule des étangs	RA: ISEIA: B1 – Watch List. Harmonia+: 0,44
	Nadelkraut	Wikipedia: | Wikispecies: | CABI
	Watercrassula	Back to the list of neophytes

Brief description

2011, Pilley, England, UK

Crassula helmsii (Kirk) Cockayne, native to New Zealand and Australia, is an aquatic or semi-terrestrial plant that colonises a wide variety of freshwater habitats. The plant’s ability to grow from stem fragments enables it to easily spread from ponds and ornamental pools into the wild. Waterfowl, mammals, downstream movement and flooding all play an important role in plant dissemination. New Zealand pigmyweed can cause major environmental problems in freshwater habitats. It forms dense vegetation mats that deplete oxygen, outcompete native species and may affect the breeding success and survival of threatened aquatic plants and amphibians. Mats choke ponds and drainage ditches, impede water flow and adversely affect recreational activities. In rivers, flow behaviour may change when the plant occurs in masses (Branquart et al. 2013).

Status and distribution in Luxembourg

Management

Our neighbouring countries have already gained experience with the management of the species and made it available in publications: Dortel & Dutartre 2018, Delbart et al. 2011, Ewald 2014, van der Loop et al. 2018.

Risk assessment

ISEIA protocol

Following its discovery in Luxembourg in July 2020, the species has been reassessed on 24 July 2020 to B1 (2+3+2+3) = Watch List by Christian Ries and Yves Krippel. Assessment before the appearance of the species in Luxembourg: B0 (2+3+2+3) = Alert List (Ries et al. 2013: 18).

Harmonia+ protocol

0,76Invasion
0,57Impact
0,44Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/16463#toDistributionMaps

Bibliography

• Branquart, E., I. Stiers, L. Triest, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2013. Harmonia database: . Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2020-02-28]
• CABI, 2019. Crassula helmsii. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-02-28]
• Dortel, F. & A. Dutartre, 2018. La Crassule de Helms (Crassula helmsii Cockayne, 1907) : Fiche d’alerte détaillée, première analyse des risques, possibilités de régulation et mesures de biosécurité. 23 p. [PDF]
• Delbart, E., A. Monty & G. Mahy, 2011. Gestion de Crassula helmsii en Belgique plus difficile qu’il n’y paraı̂t? Bulletin OEPP/EPPO Bulletin 41: 226–231. [PDF]
• Ewald, N.C., 2014. Crassula helmsii in the New Forest – a report on the status, spread and impact of this non-native invasive plant, and the efficacy of novel control techniques following a 2 year trial. Partner Annex Report for RINSE prepared on behalf of the New Forest Non-Native Plants Project. Freshwater Habitats Trust, Oxford. [PDF]
• Lambinon J. & F. Verloove, 2012. Nouvelle flore de la Belgique, du grand-duché de Luxembourg, du Nord de la France et des régions voisines. Sixième édition. Avec la collaboration de L. Delvosalle, B. Toussaint, D. Geerinck, I. Hoste, F. Van Rossum, B. Cornier, R. Schumacker, A. Vanderpoorten et H. Vannerom. Jardin botanique national de Belgique, Meise. CXXXIX + 1195 pp. ISBN : 9789072619884.
• MNHNL, 2000-. Recorder-Lux, database on the natural heritage of the Grand Duchy of Luxembourg. National Museum of Natural History, Luxembourg. Crassula helmsii (Kirk) Cockayne observed on 2020-07-23, occurrence ID MNHNL00000005TLE, via https://mdata.mnhn.lu [accessed 2021-02-22].
• MNHNL, iNaturalist & GBIF, 2020. in MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-02-28]
• Oly, M., 2022. Kartierung invasiver gebietsfremder Wasserpflanzen im Großherzotum Luxemburg, Untersuchungen zur Verbreitung von invasiven gebietsfremden Wasserpflanzen in einer beispielhaften Auswahl an Stillgewässern, Musée national d’histoire naturelle, Luxembourg. 117 pp. 
• Ries, C. & Y. Krippel, 2021. First records of 56 invasive alien vascular plants in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois 123: 115-127. [PDF 241 KB]
• 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]
• van der Loop, J.M.M., L. de Hoop, H.H. van Kleef & R.S.E.W. Leuven, 2018. Effectiveness of eradication measures for the invasive Australian swamp stonecrop Crassula helmsii. Management of Biological Invasions (2018) Volume 9, Issue 3: 343–355. DOI: https://doi.org/10.3391/mbi.2018.9.3.16 [PDF]
• Wolff, J.-P., 2020. Crassula helmsii observation at iNaturalist. URL: https://www.inaturalist.org/observations/54040409 [accessed 2020.07.24].

 Page content last updated on 2023-08-17.