|Photo by Rebekah D. Wallace, University of Georgia, Bugwood.org|
|Division:||Magnoliophyta - Flowering plants|
|Class:||Magnoliopsida – Dicotyledons|
| Ludwigia leptocarpa|
(Nutt.) H. Hara
|Natural range of Ludwigia leptocarpa from USDA NRCS Plants Database.|
Common name: Anglestem primrose-willow
Synonym: Jussiaea leptocarpa Nuttall
The specific epithet L. leptocarpa means slender-fruited.
“Repent or erect, usually branched, short-lived perennials, or rarely annual. Floral parts in 4-7’s; hypanthium not prolonged beyond ovary. Capsules longitudinally or poricidally multiseriate, rarely uniseriate. Most of the erect species produce basal offshoots, which have ovate to obovate leaves, in the late summer and fall. Bracteoles occur in pairs on the pedicel or stipe or on the base of the hypanthium.” 
"Stems erect, branched, pubescent, to 1 m tall. Leaves alternate, elliptic, pubescent, to 12 cm long and 3 cm wide; sessile or subsessile. Sepals 5-7, lanceolate, pubescent, 4.5-7 mm long, 2-3 mm wide; petals 5-7, 5.5-7.5 mm long, 4-8 mm wide. Capsules cylindric, 2-5 cm long, 2-3.5 mm in diam.; bracteoles subulate, ca. 0.5 mm long; pedicels absent or to 2 cm long; seeds uniseriate, free inside brownish endocarp." 
It is distributed throughout North America and tropical Africa.  Individuals occurring at the northern edge of the range in North America behave as an annual species while those in the southern range are perennial. 
Habitats of L. leptocarpa in the Coastal Plain in Florida include lake margins, around cypress ponds, wet ditches bordering swamps, drainage ditches bordering pine flatwoods, wet sloughs, inter-dune ponds, and growing on decaying vegetation. It has been observed growing in disturbed areas such as roadways and Kudzu dominated seepage areas. Soil types include sandy loam, loamy sand, sandy soil, peaty sand, and sandy peat. Associated species include Cephalanthus occidentalis, Eupatorium compositifolium, Hypericum walteri, Ludwigia decurrens, Nymphaea odorata, Panicum, Polygonum hirsutum, Salix nigra, Utricularia subulata, L. decurrens and L. sphaerocarpa. 
In rice paddies and other cultivated swamp lands it can become a serious weed. 
L. leptocarpa has been observed flowering May through November with peak inflorescence in September and fruiting July through November. Reproduction can be either vegetative or sexual.  Depending on the location, it can be either an annual or perennial species. 
The seeds have a specialized endocarp that remains attached and enables the seed to float. The seed capsule length is highly correlated with seed number. 
Seed bank and germination
Dolan (1984) found that seed size does influence germination, with smaller seeds germinating quicker due to the thinner seed coats for the embryos to penetrate. They also observed that populations in South Carolina have little or no seed banks.
Biomass and seed production increases under higher environmental temperatures. 
The following Hymenoptera families and species were observed visiting flowers of Ludwigia leptocarpa at Archbold Biological Station: 
Apidae: Apis mellifera, Bombus impatiens
Vespidae: Polistes fuscatus
Conservation and management
Cultivation and restoration
L. leptocarpa is also found in tropical Africa and has been used in Nigerian folk medicine for the treatment of rheumatism and dysentery (Burkill 1997). It also contains flavonoids, cerebrosides and triterpenoids. 
Flowers of Ludwigia leptocarpa
Photo by Rebekah D. Wallace, University of Georgia, [Bugwood.org
References and notesDolan, R. W. (1984). "The Effect of Seed Size and Maternal Source on Individual Size in a Population of Ludwigia leptocarpa (Onagraceae)." American Journal of Botany 71(9): 1302-1307.
- [] Encyclopedia of Life Accessed: February 6, 2016
- Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 744-5. Print.">Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 744-5. Print.
- Mabou, F. D., D. Ngnokam, et al. (2015). "New oleanane-type saponins: Leptocarposide B-D, from Ludwigia leptocarpa (Onagraceae)." Phytochemistry Letters 14: 159-164.
- Dolan, R. W. and R. R. Sharitz (1984). "Population Dynamics of Ludwigia Leptocarpa (Onagraceae) and Some Factors Affecting Size Hierarchies in a Natural Population." Journal of Ecology 72(3): 1031-1041.
- Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: October 2015. Collectors: Loran C. Anderson, K. Craddock Burks, George R. Cooley, A.H. Curtiss, Richard J. Eaton, William B. Fox, J.P. Gillespie, Robert K. Godfrey, Gary R. Knight, R. Komarek, R. Kral, Karen MacClendon, Travis MacClendon, Richard S. Mitchell, R.A. Norris, James D. Ray Jr., Annie Schmidt. States and Counties: Florida: Bay, Calhoun, Duval, Franklin, Gadsden, Hernando, Hillsborough, Jackson, Jefferson, Leon, Liberty, Madison, Okaloosa, Putnam, Santa Rosa, Taylor, Wakulla, Walton. Compiled by Tall Timbers Research Station and Land Conservancy.
- Oziegbe, M. and J. O. Faluyi (2011). "Reproductive biology of Ludwigia leptocarpa and L. adscendens sups. diffusa in Ile Ife, Nigeria." Tubitak 36: 167-173.
- Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. www.gilnelson.com/PanFlora/ Accessed: 12 DEC 2016
- Christy, E. J. and R. R. Sharitz (1980). "Characteristics of Three Populations of a Swamp Annual Under Different Temperature Regimes." Ecology 61(3): 454-460.
- Deyrup, M.A. and N.D. 2015. Database of observations of Hymenoptera visitations to flowers of plants on Archbold Biological Station, Florida, USA.