Canadian fleabane	Status LU: established. 1st record: LU & ITW 1822.
	Kanadesch Beruffkraut	Status Eur.: established. 1st record: Eur. 1600s.
	Vergerette du Canada	RA: ISEIA: C3. Harmonia+: 0,24
	Kanadisches Berufkraut	Wikipedia: | Wikispecies: | CABI
	Canadese fijnstraal	Back to the list of neophytes

Brief description

Conyza canadensis (L.) Cronquist is considered a weed and is associated mostly with perennial crops, fallows and field borders. It also occurs on roadsides and appears as an early successional species on recently disturbed land. This North American species has a high spreading capacity due to its ability to adapt to different environments combined with high reproductive potential and high seed mobility.

Status and distribution in Luxembourg

In Luxembourg, Conyza canadensis (L.) Cronquist was first reported in 1822 from a wall in Rollingen, municipality of Mersch (Krombach 1874: 344). In 1836, it was mentioned under its synonym Erigeron canadensis as an annual herbaceous plant which flowers in June-July and colonises dry and sandy environments (Tinant 1836: 424). In 1873, Koltz describes the species as common, but missing in large spaces. Found in rubble, old walls, roadsides, fallow fields around Luxembourg City. Rare in the Ardennes (Koltz 1873: 129). Between 1900-1909 huge populations were observed on the banks of the river Sauer in Diekirch (Robert 2010: 15).

The species was first documented in 1883 in Mersch by Jean Feltgen (1833-1904) (Specimen № 13971 MNHNL 2000-). The next observation was made by Léopold Reichling on 8th August 1952 in Manzenbaach, Municipality of Larochette. Since then, more than 310 observations have been recorded, especially in the central area of Luxembourg, while the north of the country is populated much more sparsely (MNHNL, iNaturalist & GBIF 2019).

According to Lambinon & Verloove (2012), the species is generally common to quite common in the environment, apart from the Ardennes and the Eifel, where it is rare (Lambinon & Verloove 2012: 709). × Conyzigeron huelsenii (Vatke) Rauschert, an intergeneric hybrid between Erigeron acris and Conyza canadensis, is very rarely observed (Lambinon & Verloove 2012: 707).

Risk assessment

ISEIA protocol

C3 (3+2+2+1) (Ries et al. 2013: 18).

Harmonia+ protocol

0,74Invasion
0,31Impact
0,24Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/15251#toDistributionMaps

Bibliography

• CABI, 2019. Conyza canadensis. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-02-28]
• Krombach, J.-H.-G., 1875. Flore du grand-duché de Luxembourg. Plantes phanérogames. 564 p. Luxembourg, Imprimerie Joris.
• 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-. Conyza canadensis (L.) Cronquist 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. Conyza canadensis (L.) Cronquist 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]
• Ries, C. & Y. Krippel, 2021 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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]
• Ries, C., Y. Krippel & M. Pfeiffenschneider, 2020 [submitted]. Risk assessment after the Harmonia+ protocol of invasive alien vascular plant species in Luxembourg. Bulletin de la Société des naturalistes luxembourgeois.
• 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.
• Tinant, F. A., 1836. Flore luxembourgeoise, ou, Description des plantes phanérogames, recueillies et observées dans le grand-duché de Luxembourg, classées d’après le système sexuel de Linnée. 512 p. Luxembourg, J. P. Kuborn.

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

	Red-osier dogwood	Status LU: established. 1st record: LU 1823, ITW 1950.
	Seideg Haartrutt	Status Eur.: established. 1st record: LU 1823.
	Cornouiller soyeux	RA: ISEIA: B1, Watch list. Harmonia+: 0,30
	Seidiger Hartriegel	Wikipedia: | Wikispecies: | CABI
	Canadese kornoeilje	Back to the list of neophytes

Brief description

Cornus sericea L. is mostly found on moist to humid eutrophic soils, where it can live with the roots submerged in water for most of the growing season. It thrives in early successional stages of riparian swamps and woodlands, but also in the understorey of open forests, along forest margins, in meadows and ruderal habitats. The plant is able to tolerate extremely cold temperatures. It is autosterile and pollinated by insects. Seeds, that are primarily dispersed by birds, have a double dormancy that needs both cold stratification and passage through bird guts to germinate. As it is commonly used as an ornamental plant and grown in gardens and public green areas, humans also contribute to the dispersion of this shrub. It is increasingly observed in the wild [in Belgium], most of the time obviously as an escape from cultivation.

In open conditions, Cornus sericea has a very high growth rate and produces abundant flowering. It can quickly cover high surfaces and make a dense canopy, which reduces the development of native vegetation, strongly decreases plant species richness, reduces tree seedling establishment and inhibits succession development. Density can exceed 100 000 stems per hectare. Under a closed canopy, the plant doesn’t produce flowers but emits long and horizontal axes that root and give rise to many stocks. This allows it to achieve great lateral exploration and to migrate to a more favourable area or to wait until opening occurs. It is considered as a weed in the floodplains and in forest openings of its area of origin (Branquart et al. 2011).

Status and distribution in Luxembourg

The next record of Cornus sericea L. is a herbarium specimen collected by Jos Witry on 1950-06-01 on/near a railway in Rumelange (Herbarium Specimen № 51729, MNHNL 2000-).

Currently, 6 records of the red-osier dogwood in Luxembourg are accessible through the MNHNL-mdata portal (MNHNL, iNaturalist & GBIF 2019).

This species originates from North America and is naturalised in Europe (mainly central). Grown for ornamental purposes in parks and along roads. Subspontaneous or naturalised here and there: old parks, groves, fresh thickets (Lambinon & Verloove 2012: 441).

Other Cornus taxa

A related species, Cornus alba L. [Syn.: Swida alba (L.) Opiz; Thelycrania alba (L.) Pojark.], originally from Siberia, is also grown for ornamental purposes. It is distinguished by its generally smaller leaves (leaf blade 4-11 cm long), erect and general non-rooting shoots and especially by the fruit stones: longer than broad, and narrow at the base, whereas they are about as long as broad and truncated-rounded at the base in C. sericea. C. alba has sometimes been mentioned in the subspontaneous state, but perhaps by confusion with C. sericea. Variants with leaf blades mixed with green and yellowish or whitish, which are not easily attached to either of these species, are frequently observed (Lambinon & Verloove 2012: 441).

Risk assessment

ISEIA protocol

B1 (2+3+3+2) = Watch list, reassessed on 2019-10-25 by C. Ries & Y. Krippel. First assessed as C0 (1+1+1+1) (Ries et al. 2013: 18).

Harmonia+ protocol

0,50Invasion
0,60Impact
0,30Risk

Worldwide distribution

CABI 2009: https://www.cabi.org/isc/datasheet/16312#toDistributionMaps

Bibliography

• Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2011. Harmonia database: Cornus sericea L. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-15]
• CABI, 2009. Cornus sericea L. [original text by Beth Middleton]. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2019-11-22]
• Koltz, J.-P.-J., 1875. Dendrologie luxembourgeoise. Catalogue des arbres, arbrisseaux et arbustes spontanés, subspontanés ou introduits dans la culture du Grand-Duché de Luxembourg. Imprimerie V. Buck, Luxembourg, 217 pp.
• 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-. Cornus sericea 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. Cornus sericea 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 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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 2021-03-02. Last proofread by Caroline Grounds on 2019-11-14.

	Wall Cotoneaster	Status LU: established. 1st record: LU & ITW 1949.
	Fächer-Zwergmëspel	Status Eur.: established. 1st record: FR 1860s-1870s.
	Cotonéaster horizontal	RA: ISEIA: C1. Harmonia+: 0,34
	Fächer-Zwergmispel	Wikipedia: | Wikispecies: | CABI
	Vlakke dwergmispel	Back to the list of neophytes

Brief description

Cotoneaster horizontalis Decne. is a small shrub that thrives in man-made habitats such as walls, railway embankments or sand quarries. It can form large spontaneous and self-sustaining populations in dunes, rock outcrops and a wide range of calcicolous grassland communities. The plant is easily dispersed by birds (Branquart et al. 2010).

Status and distribution in Luxembourg

Cotoneaster horizontalis Decne. was first documented on 6 August 1949 by François Léon Lefort (1917-1975) in Kelsbach in the Moselle valley between Grevenmacher and Machtum (Specimen № 21984 MNHNL 2000-).

The 15 occurrences in the MNHNL-mdata online portal hardly reflect the real distribution of the species (MNHNL, iNaturalist & GBIF 2019). The species seems constrained to urban areas. Commonly used as an ornamental plant, its distribution in the wild outside of urban areas is expected to increase in the future.

This melliferous species native to western China is grown for ornamental purposes in parks, gardens and roadsides. It is the most invasive exotic Cotoneaster species in sub-natural or semi-natural environments like calcicolous dry grassland, etc. (Lambinon & Verloove, 2012: 372).

Risk assessment

ISEIA protocol

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

Harmonia+ protocol

0,68Invasion
0,50Impact
0,34Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/16870#toDistributionMaps

Bibliography

• Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum, F. Verloove, 2010. Harmonia database: Cotoneaster horizontalis Decne. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-09]
• CABI, 2019. Cotoneaster horizontalis. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-02-28]
• 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-. Cotoneaster horizontalis Decne. 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. Cotoneaster horizontalis Decne. 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]
• Ries, C. & Y. Krippel, 2021 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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 2021-03-03. Last proofread by Caroline Grounds on 2019-11-14.

	Nuttall’s Waterweed	Status LU: established. 1st record: LU & ITW 1975.
	Schmuel Waasserpescht	Status Eur.: established. 1st record: BE 1939. IAS of EU concern (2017).
	Elodée de Nuttall	RA: ISEIA: A3, Black List. Harmonia+: 0,42
	Schmalblättrige Wasserpest	Wikipedia: | Wikispecies: | CABI
	Smalle waterpest	Back to the list of neophytes

Brief description

Elodea nuttallii (Planch.) H. St. John is an aquatic plant that thrives in various types of freshwater habitats, from still to slow-flowing systems and from very shallow to deep waters. It is very tolerant to water pollution and prefers warm eutrophic and calcareous waters; it is often found in species-poor macrophyte communities. This submerged perennial makes dense monospecific populations which often colonise whole water bodies, restrict water movement, cut off light, produce anoxic conditions and trap sediments in the system. Due to its quick nutrient uptake and very high growth rate, the species has been reported to outcompete several native aquatic plants (Branquart et al. 2019).

IAS of Union concern

In 2017, Elodea nuttallii (Planch.) H. St. John 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

Elodea nuttallii (Planch.) H. St. John has been first documented by Paul Verheggen in the Upper Sûre lake near Boulaide in 1975 (Parent 1983 cit. in Diederich 1984: 39) ¹.

65 records of the species are listed in the MNHNL-mdata online portal (MNHNL, iNaturalist & GBIF 2019). In Luxembourg, it is less common than Elodea canadensis and seems confined to the Gutland.

The species, observed since 1941 in the Netherlands, was harvested in 1939 in northern Belgium, but was only identified later (around 1967). It tends to locally supplant Elodea canadensis Michx. (Lambinon & Verloove 2012: 790).

Risk assessment

ISEIA protocol

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

Harmonia+ protocol

0,71Invasion
0,60Impact
0,42Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/20761#toDistributionMaps

Fact sheet

PDF fact sheet of the Nature and Forestry Administration: FR | DE

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).
• CABI, 2019. Elodea nuttallii. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-02-28]
• Branquart, E., I. Stiers, L. Triest, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum, F. Verloove, 2019. Harmonia database: Elodea nuttallii (Planch.) H. St. John. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-09]
• Diederich, P., 1984. Les monocotylédones aquatiques (excl. Potamogeton s.l.) du Grand-Duché de Luxembourg. Dumortiera 29-30: 34-41. [PDF 5 MB].
• 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 nuttallii (Planch.) H. St. John 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 nuttallii (Planch.) H. St. John 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]
• Parent, G. H., 1983. Données floristiques inédites tirées de l’herbier du docteur Paul Verheggen. Dumortiera 25 : 12-21.
• Ries, C. & Y. Krippel, 2021 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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 2021-03-03. Last proofread by Caroline Grounds on 2019-11-17.

	Tall fleabane	Status LU: established. 1st record: LU & ITW <1836.
	Jäerlecht Beuffkraut	Status Eur.: established. 1st record: DK 1810.
	Vergerette annuelle	RA: ISEIA: C1. Harmonia+: 0,03
	Feinstrahl	Wikipedia: | Wikispecies: | CABI
	Zomerfijnstraal	Back to the list of neophytes

Brief description

Erigeron annuus (L.) Pers. is a North American plant that often populates ruderal sites. Because of its ability to form dense stands, the species can become problematic from a nature conservation point of view, if it enters established natural plant communities.

Erigeron annuus is a highly variable species, in which American studies have distinguished several infraspecific taxa, generally with a more or less limited geographical distribution. Their application to naturalised populations in Europe has led to their being reported as two or even three distinct subspecies. In the environment two subspecies have often been distinguished: Erigeron annuus subsp. annuus and Erigeron annuus subsp. septentrionalis (Lambinon & Verloove 2012: 707-708).

Status and distribution in Luxembourg

Tinant (1836: 428) indicates Erigeron annuus (L.) Pers. under its synonym Aster annuus L. on “the gravels of the banks of the Moselle near Remich”. Erigeron annuus was sampled on the edge of the Moselle river near Remich before 1842 (Holandre 1842: 336). ¹ The first edition of this flora from 1829 does not mention the species (Holandre 1829: 450). According to Lefort (1949: 46), Holandre’s “Flore de la Moselle” mentions Erigeron annuus near Schengen. It seems that all these refer to original material and observations of Tinant dating before 1836. An explanation of the confusion between Remich and Schengen as location may be read in the “Flore de Lorraine” by Grodron (1857: 387) who mentions Aster annuus L. at the “Banks of the Moselle near Remich, a little beyond the French border” ², which suggests the location of the finding by Tinant might have been closer to Schengen than to Remich. In 1873, Koltz lists the species under its synonyms Stenactis alba [in the text] and Aster stenactis [in the index] and confirms that it occurs on roadsides, in hedges, lawns, and at forest edges. “Remich. T. près Schengen (Hollandre)” (Koltz 1873: 129).

The next documented observation of the species in Luxembourg dates from 1953. Marcel Etringer collected a specimen of the species on a slag heap in Dommeldange on 15th September 1953 (Specimen № 48214, MNHNL 2000-). Nowadays Erigeron annuus is quite common to quite rare in the Lorraine district (AC-AR) and very rare (RR) or non-existent in the Ardennes district (Lambinon & Verloove 2012: 707).

There are 94 observations in the Recorder-Lux database (MNHNL, iNaturalist & GBIF 2019).

Risk assessment

ISEIA protocol

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

Harmonia+ protocol

0,28Invasion
0,13Impact
0,03Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/21734#toDistributionMaps

Bibliography

• CABI, 2019. Erigeron annuus. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-03-02]
• Gordon, A., 1857. Flore de Lorraine. 504 p. 2e édition, tome 1. Nancy, Metz & Paris.
• Holandre, J.-J.-J., 1829. Flore de la Moselle, ou, Manuel d’herborisation, précédé d’un aperçu géologique sur le département et d’élémens abrégés de botanique. Tome 1. 712 p. Metz : Mme Thiel, libraire-éditeur.
• Holandre, J.-J.-J., 1842. Nouvelle flore de la Moselle, ou Manuel d’herborisation dans les environs de Metz principalement, et les autres parties du département. Tome 1 et 2, 948 p. Metz : Verronnais. Paris : Roret.
• Koltz, J.-P.-J., 1873. Prodrome de la flore du grand-duché de Luxembourg. Première partie. Plantes phanérogames. Imprimerie V. Buck, Luxembourg. 279 S.
• 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.
• Lefort, F. L., 1950. Contribution à l’histoire botanique du Luxembourg (av. 18 planches). Bull. Soc. Nat. luxemb. 54: 31-160. [PDF 6781 KB]
• MNHNL, 2000-. Erigeron annuus (L.) Pers. 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 2018-01-18]
• MNHNL, iNaturalist & GBIF, 2019. Erigeron annuus (L.) Pers. 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]
• Ries, C. & Y. Krippel, 2021 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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 2021-03-03. Last proofread by Caroline Grounds on 2019-11-18.

	Large-flowered waterweed	Status LU: established. 1st record: LU & ITW 2016.
	Dichtbliedreg Waasserpescht	Status Eur.: established. 1st record: unkn.
	Égérie dense	RA: ISEIA: A1 – Black List. Harmonia+: 0,32
	Dichtblättrige Wasserpest	Wikipedia: | Wikispecies: | CABI
	Egeria (plant)	Back to the list of neophytes

Brief description

Egeria densa Planch. is a South American aquatic plant with a very wide ecological amplitude. It thrives in a variety of freshwater habitats: while it prefers flowing systems it may also be found in still waters. The species is not light-demanding and is able to develop in deep and turbid waters. The submerged perennial makes dense monospecific populations which often colonise whole water bodies, restrict water movement, cut off light, produce anoxic conditions and trap sediments in the system. The large-flowered water weed has been reported to outcompete native aquatic plants and to adversely affect fish communities (Branquart et al. 2013).

Status and distribution in Luxembourg

Risk assessment

ISEIA protocol

A1 (2+3+3+3) = Black List. Updated on 22 June 2018 by Christian Ries and Manou Pfeiffenschneider. Former assessment: A0 (2+3+3+3) = Alert List (Ries et al. 2013: 18).

Harmonia+ protocol

0,53Invasion
0,62Impact
0,32Risk

Worldwide distribution

Source: https://www.cabi.org/isc/datasheet/20491#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. Egeria densa. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-02-28]
• MNHNL, iNaturalist & GBIF, 2019. Egeria densa 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]
• Ries, C. & Y. Krippel, 2021 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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 2021-03-03. Last proofread by Caroline Grounds on 2019-11-14.

	Parrot’s-feather	Status LU: established. 1st record: LU & ITW ~1990.
	Brasilien-Waassergras	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).

Currently 2 records are accessible through the MNHNL-mdata portal (MNHNL, iNaturalist & GBIF 2020).

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]
• Ries, C. & Y. Krippel, 2021 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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.

	Various-leaved water-milfoil	Status LU: absent. 1st record: n/a.
	Wiesselblat-Waassergras	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 2021-03-04. Last proofread by Caroline Grounds on 2019-11-20.

	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 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 [Unpublished manuscript]. First records of 56 invasive alien vascular plants in Luxembourg. MNHNL & Naturpark Öewersauer.
• 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.