The Potamogetonaceae, commonly referred to as the pondweed family, is an aquatic family of . The roughly 110 known species[ The largest genus in the family by far is Potamogeton, which contains about 100 species.
]
The family has a subcosmopolitan distribution, and is considered to be one of the most important angiosperm groups in the aquatic environment because of its use as food and habitat for aquatic animals.[Haynes, R. R. 1975. A revision of North American Potamogeton subsection Pusilli (Potamogetonaceae). Rhodora 76: 564--64]
Taxonomy
The Potamogetonaceae are currently placed in the early diverging Monocotyledon order Alismatales by the Angiosperm Phylogeny Group.[ Their concept of the family includes the plants sometimes treated in the separate family Zannichelliaceae, but excludes the genus Ruppia. So circumscribed, the family currently consists of five genera][ totalling about 120 species of perennial .
]
Marine grasses families: Zosteraceae, Cymodoceaceae, Ruppiaceae and Posidoniaceae. Related families: Potamogetonaceae, Zannichelliaceae (not consistently).
| + Families and Genera crosses (Sea grasses)
! scope="col" | Kubitzki (ed. 1998[Kubitzki (ed.) 1998. The families and genera of vascular plants, vol 4, Monocotyledons: Alismatanae and Commelinanae (except Gramineae). Springer-Verlag, Berlin.])
! scope="col" | Watson & Dallwitz (delta-intkey)[Watson & Dallwitz. Zosteraceae. The families of flowering plants. http://delta-intkey.com/angio/www/zosterac.htm]
! scope="col" | data.kew[Vascular Plant Families and Genera. List of genera in family CYMODOCEACEAE (accessed 2016-06-02) http://data.kew.org/cgi-bin/vpfg1992/genlist.pl?CYMODOCEACEAE]
! scope="col" | APWeb (mobot.org)[VASCULAR PLANT FAMILIES and GENERA. List of Genera in CYMODOCEACEAE (accessed 2016-06-02) http://www.mobot.org/mobot/research/apweb/orders/alismatalesweb.htm#Cymodoceaceael] |
|
| Zostera L. (including Heterozostera den Hartog, Macrozostera Tomlinson & Posluzny, Nanozostera Tomlinson & Posluzny, Zosterella J. K. Small) |
| (in Zostera) |
| Phyllospadix J. D. Hooker |
|
| (in Cymodocea) |
| Halodule Endlicher |
| Cymodocea König (including Amphibolis Agardh ?, Syringodium Kütz. ?, Thalassodendron den Hartog ?) |
| (in Cymodocea) |
| (in Cymodocea) |
|
| Ruppia L. |
|
| Posidonia König |
|
| + Families and Genera crosses (Potamogetonaceae)
! scope="col" | Kubitzki (ed. 1998 | Watson & Dallwitz (delta-intkey)[Watson & Dallwitz. Potamogetonaceae. The families of flowering plants. http://delta-intkey.com/angio/www/potamoge.htm]
! scope="col" | data.kew[Vascular Plant Families and Genera. List of genera in family POTAMOGETONACEAE (accessed 2016-06-02) http://data.kew.org/cgi-bin/vpfg1992/genlist.pl?POTAMOGETONACEAE]
! scope="col" | APWeb (mobot.org)[VASCULAR PLANT FAMILIES and GENERA. List of Genera in POTAMOGETONACEAE (accessed 2016-06-02) http://www.mobot.org/mobot/research/apweb/orders/alismatalesweb.htm#Potamogetonaceae] |
|
| Potamogeton L. (including Coleogeton Les & Haynes, Stuckenia Börner) |
| Groenlandia J. Gay |
| (in Ruppia in Ruppiaceae) |
| Althenia Petit (including Lepilaena Harvey) |
| Pseudalthenia Nakai (including Vleisia Tomlinson & Posluszny) |
| Zannichellia L. |
|
| (in Zannichellia L.: Potamogetonaceae) |
| (in Pseudalthenia: Potamogetonaceae) |
| Althenia Petit (including Lepilaena Harvey) |
| (in Althenia Petit) |
| (in Pseudalthenia: Potamogetonaceae) |
|
Characteristics
The plants are all aquatic perennial herbs, often with creeping and leafy branches. Their leaf blades can be either floating or submerged, and their stems are often joined. No stomata are present on the leaves. The are tetramerous: the floral formula (sepals; petals; stamens; carpels) is 4;0;4;4. The flowers have no petals. The fruit consists of one to four or .[Watson, L., and Dallwitz, M.J. (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 21 March 2010. http://delta-intkey.com/angio/www/potamoge.htm]
External links
