''Ludwigia'' (primrose-willow, water-purslane, or water-primrose) is a genus of about 82 species of

aquatic plant 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 g ...

s native to Central and South America with a cosmopolitan but mainly

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

distribution. At current, there is much debate among botanists and plant taxonomists as to the classification of many ''Ludwigia'' species. Botanists from the US Department of Agriculture are currently doing genetic analyses on plants from the Western US and South America to better classify members of this genus. The genus was named by Carl Linnaeus after Christian Gottlieb Ludwig (1709-1773), a German botanist, who was apparently not amused by this honour.

Fossil record

A large number of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

seeds A seed is an Plant embryogenesis, embryonic plant enclosed in a testa (botany), protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, includ ...

of †''Ludwigia collinsoniae'' and †''Ludwigia corneri'' have been described from

middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million ...

strata of the Fasterholt area near

Silkeborg Silkeborg () is a Danish town with a population of 49,747 (1 January 2022).Jutland Jutland ( da, Jylland ; german: Jütland ; ang, Ēota land ), known anciently as the Cimbric or Cimbrian Peninsula ( la, Cimbricus Chersonesus; da, den Kimbriske Halvø, links=no or ; german: Kimbrische Halbinsel, links=no), is a peninsula of ...

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , established ...

Selected species

Listed from the

NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...

database:NCBI taxonomy
Reviewed 2017-11-25 **

References

* Wagner, W. L., Hoch, P. C., & Raven, P. H. (2007). Revised classification of the Onagraceae. ''Systematic Botany Monographs'', ''83''.

External links

Onagraceae genera Taxa named by Carl Linnaeus {{Myrtales-stub