The Potamogetonaceae, commonly referred to as the pondweed family, is an aquatic family of monocotyledonous flowering plants. The roughly 110 known species are divided over five genera. 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.

Taxonomy

The Potamogetonaceae are currently placed in the early diverging monocot 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 aquatic plants.

PotamogetonaceaeGroenlandia Pseudalthenia Zannichellia Althenia Stuckenia Potamogeton
Groenlandia
Pseudalthenia Zannichellia Althenia
Pseudalthenia Zannichellia
Pseudalthenia
Zannichellia
Althenia
Althenia
Stuckenia Potamogeton
Stuckenia
Potamogeton

Marine grasses families: Zosteraceae, Cymodoceaceae, Ruppiaceae and Posidoniaceae. Related families: Potamogetonaceae, Zannichelliaceae (not consistently).

Families and Genera crosses (Sea grasses)
Kubitzki (ed. 1998)Watson & Dallwitz (delta-intkey)data.kewAPWeb (mobot.org)
Zosteraceae
1. Zostera L.ZosteraZostera L.Zostera L. (including Heterozostera den Hartog, Macrozostera Tomlinson & Posluzny, Nanozostera Tomlinson & Posluzny, Zosterella J. K. Small)
2. Heterozostera den HartogHeterozosteraHeterozostera (Setch.) Hartog(in Zostera)
3. Phyllospadix Hook.PhyllospadixPhyllospadix Hook.Phyllospadix J. D. Hooker
Cymodoceaceae
1. Syringodium KützSyringodiumSyringodium Kutz.(in Cymodocea)
2. Halodule Endl.HaloduleHalodule Endl.Halodule Endlicher
3. Cymodocea KönigCymodoceaCymodocea K.Koenig (including Phycoschoenus (Asch.) Nakai )Cymodocea König (including Amphibolis Agardh ?, Syringodium Kütz. ?, Thalassodendron den Hartog ?)
4. Amphibolis AgardhAmphibolisAmphibolis C.Agardh (including Pectinella J.M.Black)(in Cymodocea)
5. Thalassodendron de Hartog(name not found)Thalassodendron Hartog(in Cymodocea)
Ruppiaceae
Ruppia L.Ruppia(in Ruppia L. in Potamogetonaceae)Ruppia L.
Posidoniaceae
Posidonia KönigPosidoniaPosidonia K.KoenigPosidonia König
Families and Genera crosses (Potamogetonaceae)
Kubitzki (ed. 1998)Watson & Dallwitz (delta-intkey)data.kewAPWeb (mobot.org)
Potamogetonaceae
1. Potamogeton L.PotamogetonPotamogeton L.Potamogeton L. (including Coleogeton Les & Haynes, Stuckenia Börner)
2. Groenlandia J. GrayGroenlandiaGroenlandia J.GayGroenlandia J. Gay
(in Ruppia in Ruppiaceae)(in Ruppia in Ruppiaceae)Ruppia L.(in Ruppia in Ruppiaceae)
(in Althenia: Zannichelliaceae and Lepilaena: Zannichelliaceae)(in Althenia: Zannichelliaceae and Lepilaena: Zannichelliaceae)(in Althenia F.Petit: Zannichelliaceae and Lepilaena J.L.Drumm. ex Harv.:Zannichelliaceae)Althenia Petit (including Lepilaena Harvey)
(in Pseudalthenia including Vleisia: Zannichelliaceae)(in Pseudalthenia: Zannichelliaceae and Vleisia: Zannichelliaceae)(Pseudalthenia not found, Vleisia Toml. & Posl.: Zannichelliaceae)Pseudalthenia Nakai (including Vleisia Tomlinson & Posluszny)
(in Zannichellia L.: Zannichelliaceae)(in Zannichellia: Zannichelliaceae)(in Zannichellia L.: Zannichelliaceae)Zannichellia L.
Zannichelliaceae
1. Zannichellia L.ZannichelliaZannichellia L.(in Zannichellia L.: Potamogetonaceae)
2. Pseudalthenia Nakai (including Vleisia)Pseudalthenia (excluding Vleisia)(name not found)(in Pseudalthenia: Potamogetonaceae)
3. Althenia Petit (excluding Lepilaena Drumm. ex. Harv.)Althenia (excluding Lepilaena)Althenia F.Petit (excluding Lepilaena J.L.Drumm. ex Harv.)Althenia Petit (including Lepilaena Harvey)
4. Lepilaena Drumm. ex. Harv.LepilaenaLepilaena J.L.Drumm. ex Harv.(in Althenia Petit)
(in Pseudalthenia)VleisiaVleisia Toml. & Posl.(in Pseudalthenia: Potamogetonaceae)

Characteristics

The plants are all aquatic perennial herbs, often with creeping rhizomes 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 flowers 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 drupelets or achenes.

External links

  • at the DELTA Online Families of Flowering Plants
  • at the Germplasm Resources Information Network
  • at the Online Flora of North America
  • at the Online Flora of North America
  • at the NCBI Taxonomy Browser