Potamogeton

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Potamogeton
PotamogetonPerfoliatus2.jpg
Potamogeton perfoliatus
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Alismatales
Family: Potamogetonaceae
Genus: Potamogeton
L.
Species

80-100, see text

Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed (Elodea canadensis). The genus name means "river neighbor", originating from the Greek potamos (river) and geiton (neighbor).[1][2]

Morphology[edit]

Potamogeton species range from large to very small. Plants are sometimes annuals, but are often perennial and typically produce rhizomes which are the common overwintering form. Many species also produce specialised overwintering buds called turions which may be borne on the rhizome, on the stem, or on stolons from the rhizome. The leaves are alternate, which contrasts with the closely related genus Groenlandia, where the leaves are opposite or whorled.

In many species, all the leaves are submerged, and in these cases, they are typically thin and translucent. Some species, especially in ponds and very slow-moving waters, have floating leaves which tend to be more leathery.

Diagnostic of most species of Potamogeton is the presence of a delicate membranous sheathing scale at the leaf axil. This may be wholly attached, partly attached, or free of the leaf, and it may have inrolled margins or appear as a tube. The flowers, which are often overlooked, are composed of four rounded segments borne in a spike.

Taxonomy[edit]

Potamogeton species are found throughout the world where is standing or running water occurs. An estimated 90 species are known, but hybridisation provides an added complexity to the taxonomy. At least 26 hybrids have been observed in the British Isles alone.[2] An account of Potamogeton hybrids was currently revised, listing genetically confirmed 36 hybrids in the world.[3]

History[edit]

Alfred Fryer became interested in Potamogeton in the 1880s, and was a recognised authority on the genus. The first parts of his work The Potamogetons (Pond Weeds) of the British Isles were published in 1898. His death intervened, and the work was completed by Arthur Bennett (1843-1929). Robert Morgan (1863-1900) illustrated Fryer's contribution to the monograph, his colour plates drawing praise from later critics.[4][5]

Non-hybrid species[edit]

List source :[6]

Hybrid species[edit]

List source :[6]

Ecology[edit]

Potamogeton species are found worldwide in many aquatic ecosystems. They are important as food and habitat for animals.[2][7] Most species are not weedy, but a few can become troublesome, such as curly-leaf pondweed (Potamogeton crispus).[8]

References[edit]

  1. ^ Robert F. Thorne (2012). "Jepson Manual treatment for Potamogetonaceae (Pondweed Family)". Jepson Manual Online. University & Jepson Herbaria; Regents of the University of California. Retrieved January 6, 2012. 
  2. ^ a b c "Potamogeton". Flora of North America (eFloras) 22. Retrieved January 6, 2012. 
  3. ^ Ito, Y., and Nr. Tanaka (2013) Additional Potamogeton hybrids from China: Evidence from a comparison of plastid trnTtrnF and nuclear ITS phylogenies. APG: Acta Phytotaxonomica et Geobotanica 64 (1): 1–14
  4. ^ http://www.watsonia.org.uk/Wats16p217.pdf[dead link]
  5. ^ "Fryer, Alfred (1826 – 1912)". 
  6. ^ a b "Potamogeton". The Plant List; Version 1. (published on the internet). Royal Botanic Gardens, Kew and Missouri Botanical Garden. 2010. Retrieved January 6, 2012. 
  7. ^ "Pondweeds: Potamogeton species". Center for Aquatic and Invasive Plants; University of Florida / IFAS. 2011. Retrieved January 6, 2012. 
  8. ^ "Curly leaf pondweed: Potamogeton crispus L.". Center for Invasive Species and Ecosystem Health. May 4, 2010. Retrieved January 6, 2012. 

External links[edit]