Posidonia

Taxobox
name = "Posidonia"

---

regnum = Plantae
divisio = Magnoliophyta
classis = Liliopsida
ordo = Alismatales
familia = Posidoniaceae
familia_authority = Hutchinson
genus = "Posidonia"
genus_authority = K.D.Koenig
subdivision_ranks = Species
subdivision = See text.
range_

---

range_map_caption ="Posidonia" distribution range:"Pos(e)idonia also refers to the city of Magna Graecia later known as Paestum"

"Posidonia" is a genus of flowering plants. It contains two to nine species of marine plants ("seagrass"), found in the seas of the Mediterranean and around the south coast of Australia.

The APG system (1998) and APG II system (2003) accept this genus as constituting the sole genus in the family Posidoniaceae, which it places in the order Alismatales, in the clade monocots. The [http://www.mobot.org/MOBOT/Research/APweb/orders/alismatalesweb.htm#Alismatales AP-Website] concludes that the three families Cymodoceaceae, Posidoniaceae and Ruppiaceae form a monophyletic group. Earlier systems classified this genus in the family Potamogetonaceae or in the family Posidoniaceae but belonging to order Zosterales.

Diversity

This is a list of species that are nominally contained by the genus:Cite web|url=http://www.bsb.murdoch.edu.au/groups/seagrass/posidonia.html|title=The genus "Posidonia" König ("nom. cons.") (Posidoniaceae).|author= Mike van Keulen|publisher=Murdoch University]
*"Posidonia angustifolia" Cambridge and Kuo [Cambridge, M.L. and Kuo, J. (1979) Two new species of seagrass from Australia, "Posidonia sinuosa" and "Posidonia angustifolia" (Posidoniaceae). "Aquat. Bot. "6, 307-328 "f." Keulen]
*"Posidonia australis" Hook.f. South coast of Australia.
*"Posidonia coriacea" Cambridge and Kuo
*"Posidonia denhartogii" Kuo and Cambridge [Kuo, J. and Cambridge, M.L. (1984) A taxonomic study of the "Posidonia ostenfeldii" complex (Posidoniaceae) with descriptions of four new Australian seagrasses. "Aquat. Bot. "20, 267-95. "f." Keulen]
*"Posidonia kirkmanii" Kuo and Cambridge
*"Posidonia oceanica" (L.) Delile - This plant is endemic to the Mediterranean Sea, where it forms undersea meadows.
*"Posidonia ostenfeldii" den Hartog [den Hartog, C. (1970) Seagrasses of the World. "Verh. Kon. Ned. Akad. Wetens. Afd. Naturk. Ser. 2 "59:139 "f." Keulen]
*"Posidonia robertsoniae" Kuo and Cambridge
*"Posidonia sinuosa" Cambridge and Kuo

The species described by Linnaeus, "Posidonia oceanica", is found in the mediterranean, the rest are located around the southern coast of Australia. All the other species occur in Western Australia.This arrangement was divided into two complexes; the "Posidonia australis" and "Posidonia ostenfeldii" groups. [Kuo, J. and McComb, A.J. (1989) In: "Biology of Seagrasses. A treatise on the biology of seagrasses with special reference to the Australian region." (Eds. A.W.D. Larkum, A.J. McComb, S.A. Shepherd) (Aquatic Plant Studies 2) (Elsevier, Amsteredam). p. 6-73 "f." Keulen] Some species descriptions may only be regional characteristics, and may need further revision.

In 2006 a huge clonal colony of "Posidonia oceanica", was discovered south of the island of Ibiza. At 8 km across and possibly up to 100,000 years of age, it may be one of the largest and oldest clonal colonies on Earth. [cite web|url=http://www.ibiza-spotlight.com/news/2006/monster_plant_280506_i.htm|title= Ibiza's Monster Marine Plant|accessdate= 2007-05-09|author= Ibiza Spotlight|date= 28 May 2006]

References

External links

*APNI|name="Posidonia" K.D.Koenig "nom. cons.."|id=2346
*ITIS|ID=39059|taxon = "Posidonia"|year=2008|date=4 April
* [http://delta-intkey.com/angio/www/Posidoni.htm Posidoniaceae] in L. Watson and M. J. Dallwitz (1992 onwards) [http://delta-intkey.com/angio/ The families of flowering plants] .
* [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=55487&lvl=3&lin=f&keep=1&srchmode=1&unlock National Center for Biotechnology Information]
* [http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?9787 Germplasm Resources Information Network: "Posidonia"]
* [http://rbg-web2.rbge.org.uk/cgi-bin/nph-readbtree.pl/feout?FAMILY_XREF=&GENUS_XREF=Posidonia&SPECIES_XREF=&TAXON_NAME_XREF=&RANK= Flora Europaea: "Posidonia"]