''Myriophyllum heterophyllum'' (English: twoleaf watermilfoil or broadleaf watermilfoil) is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

from the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Myriophyllum ''Myriophyllum'' (water milfoil) is a genus of about 69 species of freshwater aquatic plants, with a cosmopolitan distribution. The center of diversity for ''Myriophyllum'' is Australia with 43 recognized species (37 endemic). These submersed ...

'' native to North America. It was first described by

André Michaux André Michaux, also styled Andrew Michaud, (8 March 174611 October 1802) was a French botanist and explorer. He is most noted for his study of North American flora. In addition Michaux collected specimens in England, Spain, France, and even Per ...

Description

''Myriophyllum heterophyllum'' is also known in English as either the twoleaf watermilfoil or broadleaf watermilfoil. It is a popular plant in

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

s or garden-ponds. The species is often misidentified or overlooked due to issues in predictions of infestations and dispersal. It is often mistaken as ''M. verticillatum'' in Europe or ''M. hippuroides'', ''M. laxum'' or ''M. pinnatum'' in North America due to their similar vegetation.

Range

''Myriophyllum heterophyllum'' is endemic to the eastern part of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

and

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. In the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

, the plant has also been found in

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia a ...

and the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

Citizen science Citizen science (CS) (similar to community science, crowd science, crowd-sourced science, civic science, participatory monitoring, or volunteer monitoring) is scientific research conducted with participation from the public (who are sometimes re ...

observations also suggests occurrences in the western-part of the United States and

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

Invasive species

In the

the species is naturalised in the wild and poses a thread to biodiversity. It grows rapidly and can form dense mats just underneath the water surface, causing reduced availability of

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

and

sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...

. The European Union considers the risk of the species spreading high within the EU. As a preventative measure, ''Myriophyllum heterophyllum'' is included since 2017 in the list of Invasive Alien Species of Union concern (the Union list). This implies a ban of the import, trade, sale and transport of the species within the EU.

References

heterophyllum {{saxifragales-stub