''Najas marina'' is a species of aquatic plant known by the common names spiny water nymph, spiny naiad and holly-leaved naiad. It is an extremely widespread species, reported across Europe, Asia, Africa, Australia, the Americas and many oceanic islands. It can be found in many types of freshwater and

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estu ...

aquatic habitat, including bodies of alkaline water.

Description

''Najas marina'' is an annual producing a slender, branching stem up to 40 or 45 centimeters in maximum length. The evenly spaced leaves are up to 4 centimeters long, 1 to 3 millimeters wide, and edged in tiny sawlike teeth. The leaf has prickles along its midvein. Minute stalkless, green flowers occur in the leaf axils. The plant is dioecious, with male and female flower types occurring on separate individuals. In the British Isles it is possible that only female plants occur. It flowers in mid-summer.

Varieties and subspecies

A long list of varietal and subspecific names have been proposed over the years. At present, only nine are widely accepted: *''Najas marina'' subsp. ''arsenariensis'' (Maire) L.Triest -

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

*''Najas marina'' var. ''brachycarpa'' Trautv. - China and

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

*''Najas marina'' subsp. ''commersonii'' L.Triest -

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

Mauritius Mauritius ( ; french: Maurice, link=no ; mfe, label= Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It ...

, Réunion *''Najas marina'' var. ''grossidentata'' Rendle -

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

and

Manchuria Manchuria is an exonym (derived from the endo demonym " Manchu") for a historical and geographic region in Northeast Asia encompassing the entirety of present-day Northeast China (Inner Manchuria) and parts of the Russian Far East (Outer M ...

*''Najas marina'' var. ''intermedia'' (Wolfg. ex Gorski) Rendle -

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 ...

Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...

, China, Sri Lanka *''Najas marina'' var. ''marina'' *''Najas marina'' subsp. ''marina'' *''Najas marina'' subsp. ''sumatrana'' (W.J.de Wilde) L.Triest - Sumatra *''Najas marina'' var. ''zollingeri'' Rendle - Bali

Distribution and habitat

''Najas marina'' has a wide, almost circumglobal distribution in temperate and tropical regions. It occurs in mesoeutrophic water over deep peat or mud. It was first recorded in the British Isles in 1883 at

Hickling Broad Hickling Broad is a nature reserve 4 km south-east of Stalham, north-east of Norwich in Norfolk. It is managed by the Norfolk Wildlife Trust. It is a National Nature Reserve and part of the Upper Thurne Broads and Marshes Site of Speci ...

in Norfolk where it had become established. Populations declined in the 1960s because of pollution, but action has been taken to reduce the level of nutrients in the Norfolk Broads and the water quality has improved.

Fossil record

One

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

seed of ''Najas marina'' has been extracted from

borehole A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petrol ...

samples of the Middle Miocene fresh water deposits in Nowy Sacz Basin,

West Carpathians The Western Carpathians are a mountain range and geomorphological province that forms the western part of the Carpathian Mountains. The mountain belt stretches from the Low Beskids range of the Eastern Carpathians along the border of Poland wit ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populou ...

.Łańcucka-Środoniowa M.: Macroscopic plant remains from the freshwater Miocene of the Nowy Sącz Basin (West Carpathians, Poland) zczątki makroskopowe roślin z miocenu słodkowodnego Kotliny Sądeckiej (Karpaty Zachodnie, Polska) Acta Palaeobotanica 1979 20 (1): 3-117.

References

External links

Jepson Manual TreatmentPhoto gallery
{{Taxonbar, from=Q158868 marina Aquatic plants Plants described in 1753 Taxa named by Carl Linnaeus Flora of North America Flora of South America Flora of Africa Flora of temperate Asia Flora of tropical Asia Flora of Europe Flora of Australia Dioecious plants