''Littorella'' is a genus of two to three species of aquatic plants. Many plants live their entire lives submersed, and reproduce by

stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

s, but some are only underwater for part of the year, and flower when they are not underwater.

Classification

Molecular data show ''Littorella'' to be sister to the rest of the genus ''

Plantago ''Plantago'' is a genus of about 200 species of flowering plants in the family Plantaginaceae, commonly called plantains or fleaworts. The common name plantain is shared with the unrelated cooking plantain. Most are herbaceous plants, though a ...

''. Thus,

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

s would allow it to be considered either as a separate genus or as part of ''Plantago''. Some researchers, particularly Rahn in the 1990s, have considered ''Littorella'' to be located within ''Plantago'', but this does not seem to be required given the molecular data and a closer look at morphology.

Species

*''

Littorella uniflora ''Littorella uniflora'' (vernacular name: (American) shoreweed) is a species of aquatic flowering plant native to the Azores, Morocco, most of Europe excluding the dry southeast, Iceland, and the Faroes. It prefers to live mostly submerged in nut ...

''. Found in Europe from

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...

to the

black sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Roma ...

. *'' Littorella americana'' from northern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. *''

Littorella australis ''Littorella'' is a genus of two to three species of aquatic plants. Many plants live their entire lives submersed, and reproduce by stolons, but some are only underwater for part of the year, and flower when they are not underwater. Classific ...

'' from

patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...

, in southern

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

and

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

, and the

Falkland Islands The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubouzet ...

Some authors have treated ''L. uniflora'' and ''L. americana'' to be one species, but molecular data show ''L. americana'' to be more closely related to ''L. australis'' than it is to ''L. uniflora'', which argues for recognizing three species. Other considerations, such as the wider range and more frequent flowering of ''L. uniflora'', also argue for separate species. It seems likely that the genus originated in Europe and first spread to North America, and from there to South America, with both events happening in the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

or later.

Distribution

The European species is found in a wide range of habitats, from

arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

. The North and South American species are found in a more limited range of

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

climates.

References

External links

{{Taxonbar, from=Q159381 Plantaginaceae Plantaginaceae genera Taxa named by Carl Linnaeus