Narrow-leaved Michaelmas-daisy	Status LU: established. 1st record: LU 1934, ITW 1949.
	Schmuelbliedreg Aster	Status Eur. : established. 1st record: UK 1633.
	Aster à feuilles lancéolées	RA: ISEIA: C1. Harmonia+: 0,15
	Lanzettblättrige Aster	Wikipedia: | Wikispecies: | CABI
	Smalle Aster	Back to the list of neophytes

Brief description

Aster lanceolatus Willd. thrives both in ruderal and riparian areas, especially on rich and moist to humid soils. Commonly planted in gardens, it then gets propagated through fly-tipping of green waste. Seed development depends on climatic conditions. Asters are rhizomatous species, and can propagate clonally. They easily form dense and wide monospecific colonies, displacing native wetland plants, and favouring the sedimentation and stabilization of riverbanks, which reduces the ability of rivers to meander and flood (Branquart et al. 2010).

Status and distribution in Luxembourg

In Luxembourg, Aster lanceolatus Willd. was first collected by Jos Witry on 24th August 1934 in Grevenmacher (Specimen № 52294, MNHNL 2000-b). It is not specified if it was cultivated or not.

The species was first recorded in the wild by François Léon Lefort (1917-1975) on 30 September 1949 by the river Sûre in Diekirch (Specimen № 22445, MNHNL 2000-b).

Currently, 15 records of the species are accessible through the MNHNL-mdata portal, most of them in the Moselle valley (MNHNL, iNaturalist & GBIF 2019).

According to Lambinon & Verloove (2012: 706), the species occurs as quite common to quite rare (AC-AR) around villages, vacant lots, wastelands, and river banks, as subspontaneous or naturalised.

Other Aster taxa

1. Aster dumosus L. (Syn.: Symphyotrichum dumosum (L.) G. L. Nesom): the bushy aster is first reported by Tinant on the banks of the Moselle (Wirtgen 1842: 89; Lefort 1950: 41). A hybrid Aster dumosus x novi-belgii was collected by Paul Grzonka and Léopold Reichling on 29 September 1959 in Bech-Kleinmacher in the Moselle valley (MNHNL 2000-b).
2. Aster novi-belgii L.: confused Michaelmas-daisy, first mentioned in 1872 in the wild in Luxembourg.
3. Aster ×salignus: this hybrid between A. lanceolatus x A. novi-belgii is much confused with both its parents, particularly A. lanceolatus. The common michaelmas daisy was first mentioned by Yves Krippel in 2001 at Pällembierg (MNHNL 2000-b).

Risk assessment

ISEIA protocol

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

Harmonia+ protocol

Overall risk score 0,15 = (Overall Invasion score 0,36 x Overall Impact score 0,40) (Ries et al. 2020).

Worldwide distribution

Bibliography

• Branquart, E., S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2010. Harmonia database: Aster lanceolatus Willd. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-10-16]
• CABI, 2020. Aster lanceolatus. 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.
• 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-a. Aster novi-belgii 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 2019-09-03]
• MNHNL, 2000-b. 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 2019-10-24]
• MNHNL, iNaturalist & GBIF, 2019. Aster lanceolatus 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 2019-09-06]
• 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]
• Schmidt, G., 1993. Fiches de terrain, cartographie des biotopes de la commune de Remerschen. Fondation Oeko-Fonds, Luxembourg. Non published document.
• Wirtgen, P., 1842. Prodromus der Flora der preussischen Rheinlande. Henry & Cohen, Bonn. 242 p.

 Page content last updated on 2021-03-02. Last proofread by Caroline Grounds on 2019-11-13.

	Warty-cabbage	Status LU: established. 1st record: LU & ITW 1874.
	Orientalesch Zackescheekchen	Status Eur.: established. 1st record: UK 1731.
	Bunias d’Orient	RA: ISEIA: C1. Harmonia+: 0,30
	Orientalisches Zackenschötchen	Wikipedia: | Wikispecies: | CABI
	Grote hardvrucht	Back to the list of neophytes

Brief description

Bunias orientalis L. is a fast growing perennial plant needing a lot of light. On nutrient-rich and disturbed soils, the species can build up dense populations quicker than potential competitors. Disturbances favour the species, which can also survive in closed vegetation stands unless it is shaded. The plant occurs mainly in ruderal habitats and on road embankments.

Status and distribution in Luxembourg

Bunias orientalis L. was first documented in 1874 in Luxembourg. It was first found during a botanical stroll by Dr. Édouard Aschman in June 1874 in an alfalfa field on the upper part of Clausen towards Fetschenhof (Fischer 1886: 58; Koltz 1877: 8).

If we consider the previous record as being found in cultivated conditions, the species was first recorded in the wild by Jean Feltgen (1833-1904) in 1885 on a railway dam in Lorentzweiler (Obs. key: DSS00439000014NR, MNHNL 2000-).

Another early finding was on 1949-05-25 in the Municipality of Mersch (Beck et al. 1950).

Since then more than 50 occurrences have been reported, mainly in the south and the central parts of Luxembourg (MNHNL, iNaturalist & GBIF 2021, MNHNL 2000-). The species seems to expand in the south of Luxembourg into dry grassland habitats with new records at Haut des Saulnes (Rodange), at Roudebierg (Dudelange) and Giele Botter (Niedercorn / Pétange) (Email by Jan Herr, 2019-06-12).

The melliferous species is quite common to quite rare (AC-AR) in the Lorraine environment (Lambinon & Verloove 2012: 256).

Risk assessment

ISEIA protocol

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

Harmonia+ protocol

Overall risk score 0,30 = (Overall Invasion score 0,67 x Overall Impact score 0,44) (Ries et al. 2020).

Worldwide distribution

Bibliography

• Beck, E., Jungblut, F., Lefort, F.L., Reichling, L., Stumper, R., 1950. Herborisations faites dans le Grand-Duché de Luxembourg en 1949 (av. 2 fig. et 7 planches). Bull. Soc. Nat. luxemb. 54: 161-208. [PDF 1745 KB]
• CABI, 2009. Bunias orientalis [original text by Agnese Priede]. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2020-02-28]
• Fischer, M.-E., 1886. Plantes Phanérogames Nouvelle ou Rares de la Flore luxembourgeoise. Recueil des mémoires et des travaux publiés par la Société de botanique du grand-duché de Luxembourg 11: 50-68. [PDF 12 MB]
• Koltz, J.-P.-J., 1877. Compte-rendu des travaux de la Société botanique pour l’exercice 1874, présenté à l’assemblée générale du 27 février 1875. Recueil des mémoires et des travaux publiés par la Société de Botanique du Grand-Duché de Luxembourg 2-3 : 7-9.
• 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-. Bunias orientalis 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 2019-09-05]
• MNHNL, iNaturalist & GBIF, 2019. Bunias orientalis 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 2019-09-06]
• 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 2021-04-14. Last proofread by Caroline Grounds on 2019-11-14.

	Curly waterweed	Status LU: present. 1st record: 2024
	Gekréngelt Waasserpescht	Status Eur.: established. 1st record: UK 1944.1 IAS of EU concern (2016).
	Elodée crépue	RA: ISEIA: A1, Alert List. Harmonia+: 0,39.
	Wechselblatt-Wasserpest	Wikipedia:  | Wikispecies: | CABI
	Verspreidbladige waterpest	Back to the list of neophytes

Brief description

Lagarosiphon major Ridl. Moss ex Wager, Curly Waterweed, preferentially develops in clear, still or slow-flowing water systems. It can live in a wide range of trophic conditions providing that a silty or sandy bottom rich in nutrients is available. It prefers well-lit environments. The plant 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 species has been reported to outcompete native aquatic plants and to affect associated populations of aquatic invertebrates and vertebrates. Dense beds provide a poor habitat for aquatic animals and are not consumed by fish. They interfere with recreational activities and increase the risk of adjacent land flooding (Branquart et al. 2013).

IAS of Union concern

In 2016, Lagarosiphon major Ridl. Moss ex Wager 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

The first documented observation of Lagarosiphon major Ridl. Moss ex Wager in Luxembourg was made in 2024 by Max Oly. The species was found on 26 August in a pond in the park of Munsbach Castle. Here are the observer’s comments. The population is located in a rather small and approx. 1 metre deep foil pond at the castle. The vegetation is quite natural with cattails, sedges and milfoil. The two invasive species (L. major and Crassula helmsii) have probably been deliberately introduced into the pond. Lagarosiphon is submersed and occupies a large part of the water body.

Risk assessment

ISEIA protocol

A1 (2+3+3+3) = Alert List (Ries et al. 2013: 18).

Harmonia+ protocol

Overall risk score 0,39 = (Overall Invasion score 0,60 x Overall Impact score 0,65) (Ries et al. 2020).

Worldwide distribution

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: Lagarosiphon major Ridl. Moss ex Wager. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-11-21]
• CABI, 2021. Lagarosiphon major. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2021-03-04]
• MNHNL, iNaturalist & GBIF, 2020. Lagarosiphon major 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 2024-10-03. Last proofread by Caroline Grounds on 2019-11-19.

1. Cf. CABI 2021.[↩]

	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

Overall risk score 0,24 = (Overall Invasion score 0,74 x Overall Impact score 0,31) (Ries et al. 2020).

Worldwide distribution

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. 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 & 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

Cornus sericea L. was first mentioned for Luxembourg under its synonym Cornus stolonifera Michx. as introduced in 1823 in the Schrassig Park (Koltz 1875: 94). It was first documented in Luxembourg as its subspecies Cornus sericea ssp. sericea under its synonym Cornus stolonifera Michx. by Jean Feltgen in July 1887 in the park of Kockelscheuer, municipality of Luxembourg (Herbier specimen № 10659, MNHNL 2000-).

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

Overall risk score 0,30 = (Overall Invasion score 0,50 x Overall Impact score 0,60) (Ries et al. 2020).

Worldwide distribution

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. 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 2021-08-23. 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

Overall risk score 0,34 = (Overall Invasion score 0,68 x Overall Impact score 0,50) (Ries et al. 2020).

Worldwide distribution

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. 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 2021-03-03. Last proofread by Caroline Grounds on 2019-11-14.

	Nuttall’s Waterweed	Status LU: established. 1st record: LU & ITW 1975.
	Schmuelbliedereg 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. 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).

Elodea nuttallii (Planch.) H. St. John is so far less common in Luxembourg than the Canadian waterweed. 

An identification sheet of the species has been published by the MECB in French and German.

Management

Action plan

The action plan dedicated to Nuttall’s Waterweed was published September 2020:

→ Finalised Action Plan for Elodea nuttallii (Pfeiffenschneider & Hoppe 2020).

Risk assessment

ISEIA protocol

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

Harmonia+ protocol

Overall risk score 0,42 = (Overall Invasion score 0,71 x Overall Impact score 0,60) (Ries et al. 2020).

Worldwide distribution

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]
• 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. 
• Parent, G. H., 1983. Données floristiques inédites tirées de l’herbier du docteur Paul Verheggen. Dumortiera 25 : 12-21.
• Pfeiffenschneider, M. & F. Hoppe, 2020. Plan d’action pour espèces exotiques envahissantes au Grand–Duché de Luxembourg : Elodéede Nuttall, Elodea nuttallii (Planch.) H. St. John. Version 23/09/2020. Administration de la nature et des forêts, Luxembourg. 22pp.
• 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 2024-07-31. Last proofread by Caroline Grounds on 2019-11-17.

1. Diederich 1984, p. 39: Oesling : Boulaide, au lac, K7.48. 1975. herb. Verheggen (PARENT. 1983).[↩]

	Tall fleabane	Status LU: established. 1st record: LU & ITW <1836.
	Jäerlecht Beruffkraut	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).

Risk assessment

ISEIA protocol

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

Harmonia+ protocol

Overall risk score 0,03 = (Overall Invasion score 0,28 x Overall Impact score 0,13) (Ries et al. 2020).

Worldwide distribution

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. 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 2023-02-03. Last proofread by Caroline Grounds on 2019-11-18.

1. Cette plante a été trouvée sur les bords de la Moselle près de Remich, d’où proviennent mes échantillons.[↩]
2. Bords de la Moselle près de Remich, un peu au-delà de la frontière de France[↩]

	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

Egeria densa Planch. was observed twice in 2016 in the Eisch valley East of Hobscheid (mdata.mnhn.lu) and in 2019 in Luxembourg City (MNHNL, iNaturalist & GBIF 2019).

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

Overall risk score 0,32 = (Overall Invasion score 0,53 x Overall Impact score 0,62) (Ries et al. 2020).

Worldwide distribution

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]
• 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 2023-08-17. Last proofread by Caroline Grounds on 2019-11-14.

	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

Overall risk score 0,51 = (Overall Invasion score 0,68 x Overall Impact score 0,75) (Ries et al. 2020).

Worldwide distribution

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.