''Myriophyllum variifolium'' is a species of

water milfoil ''Myriophyllum'' (water milfoil) is a genus of about 69 species of freshwater aquatic plants, with a cosmopolitan distribution. The center of diversity for ''Myriophyllum'' is Australia with 43 recognized species (37 endemic). These submersed ...

native to eastern Australia where it grows in

aquatic habitat Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies s ...

such as

pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from th ...

s and streams.

Joseph Dalton Hooker Sir Joseph Dalton Hooker (30 June 1817 – 10 December 1911) was a British botanist and explorer in the 19th century. He was a founder of geographical botany and Charles Darwin's closest friend. For twenty years he served as director of t ...

described the species in 1840, from material collected in the Lachlan River, as well as Tasmania. The Tasmanian material resembled the description more closely, and the New South Wales material has been separated as a different species, hence the original Tasmanian material was made the neolectotype. ''Myriophyllum variifolium'' is found from southeastern South Australia and western Victoria, and eastern Victoria through New South Wales into southeastern Queensland. It also occurs in central and eastern Tasmania. It grows in shallow still or slowly-moving water deep An aquatic herbaceous plant, ''M. variifolium'' grows to about in length, its smooth stems around in diameter. ''Myriophyllum variifolium'' intergrades with the very similar '' M. simulans'' in western Victoria and South Australia. Molecular work indicated that ''M. variifolium'' and related species require further genetic investigation and that as yet undescribed cryptic species are likely; two lineages of ''M. variifolium'' were identified and both were paraphyletic to one lineage of ''M. simulans'' and an undescribed species. ''Myriophyllum variifolium'' can be distinguished from ''M. simulans'' by its fruit—the former has yellowish brown cylindrical fruit around 1.5 mm long, while the latter has reddish purple oval fruit around 1 mm long. The leaves of ''M. variifolium'' are arranged in whorls of five, while those of ''M. simulans'' are arranged in whorls of three or four. A desirable plant in pond or aquarium planting, ''M. variifolium'' provides shelter for eggs and

juvenile fish Fish go through various life stages between fertilization and adulthood. The life of a fish start as spawned eggs which hatch into immotile larvae. These larval hatchlings are not yet capable of feeding themselves and carry a yolk sac which ...

(fry). It needs to be planted in at least of water.

References

{{Taxonbar, from=Q17777167 variifolium Freshwater plants Flora of New South Wales Flora of South Australia Flora of Tasmania Plants described in 1840