''Althenia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

aquatic plants Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

of the family

Potamogetonaceae 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 six genera. The largest genus in the family by far is ''Potamogeton'', w ...

. This has long been a group of two species in the Mediterranean Europe and South Africa, but in 2016 was revised to include an Australasian relative, ''Lepilaena''.

Description

This genus is made up of aquatic herbs. The bristle-like leaves are clustered at the nodes. The wider bases produce broad ligules. The flowers are unisexual. The male flowers have a perianth made of three minute scales and have a single stamen. The female flowers have a perianth made of one to three segments. The gynoecium has three carpels with a single pendulous ovule in each ovary. The filiform styles gradually pass into the carpels and the stigmas are large and oblique. The mature carpels are oblique and compressed with a winged or thickened margin. The seeds are pendulous, oblong and compressed. The embryo is straight.

Species

:* '' Althenia australis'' (aquatic) :* ''

Althenia bilocularis ''Althenia bilocularis'' is a plant found in both Australia and New Zealand, in fresh to brackish waters. In Australia it is found in all mainland states with the exception of the Northern Territory. In New Zealand it is found on the North, Sou ...

'' (aquatic) :* '' Althenia cylindrocarpa'' (brackish water, marine) :* '' Althenia filiformis'' :* '' Althenia marina'' (marine) :* '' Althenia orientalis'' :* '' Althenia patentifolia'' :* '' Althenia preissii'' (aquatic)

Lepilaena

''Lepilaena'' was a genus of aquatic and

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

comprising 6 or more species

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to coastal and

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

or alkaline inland waters of temperate

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

, and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. The species are appended with common names that derive from their description as water-mats; for example, ''L. australis'' is referred to as Austral water-mat and ''L. marina'' as Sea water-mat. Interpretation of molecular evidence for this poorly studied genus suggests a close affinity with ''

Zannichellia ''Zannichellia'' (common name horned pondweed) is a genus of submerged aquatic flowering plant, with threadlike leaves and tiny flowers. It is fully adapted to an aquatic life cycle, including underwater pollination. There are perhaps five spec ...

'', another genus of aquatic plants. Two species are noted for their occurrence in marine environs, ''L. cylindrocarpa'' and ''L. marina'', in estuaries and tidal flats. ''L. cylindrocarpa'' is also found in a variety of brackish inland waters of mainland Australia. Other species may be found in habitats of fresh to brackish, still or slowly moving, coastal or inland waters. Based on the molecular and morphological evidence, all the species been transferred to the genus ''Althenia'' in 2016. Ito, Y., Nr. Tanaka, P. García-Murillo, A.M. Muasya (2016
A new delimitation of the Afro-Eurasian plant genus ''Althenia'' to include its Australasian relative, ''Lepilaena'' (Potamogetonaceae) – evidence from DNA and morphological data
''

Molecular Phylogenetics and Evolution ''Molecular Phylogenetics and Evolution'' is a peer-reviewed scientific journal of evolutionary biology and phylogenetics. The journal is edited by E.A. Zimmer. Indexing The journal is indexed in: *EMBiology *Journal Citation Reports *Scopus ...

'' 98: 261-270.

References

External links

Flora of Western Australia
* * Aquatic plants Potamogetonaceae Alismatales genera {{Monocot-stub