Potamogetonaceae
Encyclopedia
The Potamogetonaceae, commonly referred to as the pondweed family, is an aquatic family of monocotyledon
ous flowering plant
s. There are roughly 120 species spread across six genera in the Potamagetonaceae. The largest genus in the family by far is Potamogeton
, which contains about 100 species.
The family has a sub-cosmopolitan 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.
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 six genera: Althenia
, Groenlandia
, Lepilaena
, Potamogeton
, Stuckenia, and Zannichellia
, totalling about 120 species of perennial aquatic plant
s.
s and leafy branches. Their leaf
blades can be either floating or submersed, and their stems are often joined. No stomata are present on the leaves. The flower
s are tetramerous: the floral formula (sepals; petals; stamens; carpels) is [4;0;4;4]. The flowers have no petals. The fruit
consists of 1-4 drupelets or achene
s.
Monocotyledon
Monocotyledons, also known as monocots, are one of two major groups of flowering plants that are traditionally recognized, the other being dicotyledons, or dicots. Monocot seedlings typically have one cotyledon , in contrast to the two cotyledons typical of dicots...
ous flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s. There are roughly 120 species spread across six genera in the Potamagetonaceae. The largest genus in the family by far is Potamogeton
Potamogeton
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...
, which contains about 100 species.
The family has a sub-cosmopolitan distribution
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
, 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 is currently placed in the early diverging monocot order AlismatalesAlismatales
Alismatales is an order of flowering plants including about 2500 species. Pleants assigned to this order are mostly tropical or aquatic.-Description:...
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 six genera: Althenia
Althenia
Althenia is a genus of aquatic plants of the family Potamogetonaceae ....
, Groenlandia
Groenlandia
Groenlandia is a genus of aquatic plants of the family Potamogetonaceae....
, Lepilaena
Lepilaena
Lepilaena is a genus of aquatic and marine flowering plant comprising 6 or more species endemic to coastal and brackish or akaline inland waters of temperate Australia, Tasmania, and New Zealand....
, Potamogeton
Potamogeton
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...
, Stuckenia, and Zannichellia
Zannichellia
Zannichellia is a genus of submerged aquatic flowering plant. The genus is fully adapted to an aquatic life cycle including underwater pollination. Zannichellia has threadlike leaves and tiny flowers....
, totalling about 120 species of perennial aquatic plant
Aquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...
s.
Characteristics
The plants are all aquatic perennial herbs, often with creeping rhizomeRhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s and leafy branches. Their leaf
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
blades can be either floating or submersed, and their stems are often joined. No stomata are present on the leaves. The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are tetramerous: the floral formula (sepals; petals; stamens; carpels) is [4;0;4;4]. The flowers have no petals. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
consists of 1-4 drupelets or achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
s.
Genera
- AltheniaAltheniaAlthenia is a genus of aquatic plants of the family Potamogetonaceae ....
- GroenlandiaGroenlandiaGroenlandia is a genus of aquatic plants of the family Potamogetonaceae....
- LepilaenaLepilaenaLepilaena is a genus of aquatic and marine flowering plant comprising 6 or more species endemic to coastal and brackish or akaline inland waters of temperate Australia, Tasmania, and New Zealand....
- PotamogetonPotamogetonPotamogeton 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...
- Stuckenia
- ZannichelliaZannichelliaZannichellia is a genus of submerged aquatic flowering plant. The genus is fully adapted to an aquatic life cycle including underwater pollination. Zannichellia has threadlike leaves and tiny flowers....
External links
- Angiosperm Phylogeny Website
- Potamogetonaceae at the DELTA Online Families of Flowering Plants
- Potamogetonaceae at the Germplasm Resources Information Network
- Potamogetonaceae at the Online Flora of North America
- Zannichelliaceae at the Online Flora of North America
- Potamogetonaceae at the NCBI Taxonomy Browser