''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, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...

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 ( ; from Ancient Greek 'branch') 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 ...

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''. Found in Europe from

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

to the

Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea 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 bound ...

. *'' Littorella americana'' from northern

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. *'' Littorella australis'' from

patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

, in southern

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

and

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

, and the

Falkland Islands The Falkland Islands (; ), commonly referred to as The Falklands, 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 from Cape Dub ...

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 ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

or later.

Distribution

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

arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

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 east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...

. 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 (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

climates.

References

{{Authority control Plantaginaceae Plantaginaceae genera Taxa named by Carl Linnaeus