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

aquatic plant Aquatic plants, also referred to as hydrophytes, are vascular plants and Non-vascular plant, non-vascular plants that have adapted to live in aquatic ecosystem, aquatic environments (marine ecosystem, saltwater or freshwater ecosystem, freshwater ...

s with a

cosmopolitan Cosmopolitan may refer to: Internationalism * World citizen, one who eschews traditional geopolitical divisions derived from national citizenship * Cosmopolitanism, the idea that all of humanity belongs to a single moral community * Cosmopolitan ...

but mainly

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

distribution. Currently (2023), 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 Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

after Christian Gottlieb Ludwig (1709-1773).

Fossil record

The oldest known remains of the genus are known from

Eckfelder maar The Eckfelder Maar is a former volcanic lake, that was formed during the Middle Eocene around 44.3 million years ago and is thus the oldest known maar. It lies in the southwestern Eifel mountains near Manderscheid in Germany.

in Germany, dating to the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. ''Ludwigia'' pollen was also found associated with beetles belonging to the families

Buprestidae Buprestidae is a family (biology), family of beetles known as jewel beetles or metallic wood-boring beetles because of their glossy Iridescence, iridescent colors. Larvae of this family are known as flatheaded borers. The family is among the lar ...

and

Scarabaeidae The family Scarabaeidae, as currently defined, consists of over 35,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change. Several groups formerly tre ...

, suggesting that these flowers were likely pollinated by beetles rather than hymenopterans as is typical in modern species. 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 preserve ...

seeds In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the ...

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

middle Miocene The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0. ...

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

of the Fasterholt area near

Silkeborg Silkeborg () is a Denmark, Danish town with a population of 52,571 (1 January 2025).Jutland Jutland (; , ''Jyske Halvø'' or ''Cimbriske Halvø''; , ''Kimbrische Halbinsel'' or ''Jütische Halbinsel'') is a peninsula of Northern Europe that forms the continental portion of Denmark and part of northern Germany (Schleswig-Holstein). It ...

Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...

Selected species

Listed from the

NCBI The National Center for Biotechnology Information (NCBI) is part of the 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 NCBI is loca ...

database:NCBI taxonomy
Reviewed 2017-11-25 * '' Ludwigia adscendens'' * '' Ludwigia alata'' * '' Ludwigia alternifolia'' * '' Ludwigia anastomosans'' * '' Ludwigia arcuata'' * '' Ludwigia bonariensis'' * '' Ludwigia brevipes'' * '' Ludwigia curtissii'' * '' Ludwigia decurrens'' * '' Ludwigia erecta'' * '' Ludwigia glandulosa'' * '' Ludwigia grandiflora'' * '' Ludwigia helminthorrhiza'' * '' Ludwigia hirtella'' * '' Ludwigia hexapetala'' * '' Ludwigia hyssopifolia'' * '' Ludwigia inclinata'' * '' Ludwigia lanceolata'' * '' Ludwigia leptocarpa'' * '' Ludwigia linearis'' * '' Ludwigia linifolia'' * '' Ludwigia longifolia'' * '' Ludwigia maritima'' * '' Ludwigia microcarpa'' * '' Ludwigia natans'' * '' Ludwigia octovalvis'' * '' Ludwigia palustris'' * '' Ludwigia peploides'' * '' Ludwigia peruviana'' * '' Ludwigia pilosa'' * '' Ludwigia polycarpa'' * '' Ludwigia ravenii'' * '' Ludwigia repens'' * '' Ludwigia sedioides'' * '' Ludwigia simpsonii'' * '' Ludwigia spathulata'' * '' Ludwigia sphaerocarpa'' * '' Ludwigia suffruticosa'' * '' Ludwigia virgata''

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