Ludwigia leptocarpa (USA) ?

Ludwigia leptocarpa (Nutt.) H.Hara, J. Jap. Bot. 28: 292 1953. (syn: Adenola glauca Rafin.; Jussiaea aluligera Miq.; Jussiaea biacuminata Rusby; Jussiaea heterophylla Salzm. ex Micheli; Jussiaea leptocarpa Nutt.; Jussiaea leptocarpa var. aluligera (Miq.) Jonker; Jussiaea leptocarpa f. biacuminata (Rusby) Munz;  Jussiaea leptocarpa var. meyeriana (Kuntze) Munz; Jussiaea marcgravii DC.; Jussiaea miquelii Sagot ex Micheli; Jussiaea pilosa Kunth; Jussiaea pilosa var. glabra Hoehne; Jussiaea pilosa var. pterocarpa Hassl.; Jussiaea pilosa var. robustior J. D. Sm.; Jussiaea pseudoheterophylla Salzm. ex Micheli; Jussiaea schottii Micheli; Jussiaea seminuda H. Perrier; Jussiaea surinamensis Miq.; Jussiaea variabilis G.F.W. Mey.; Jussiaea variabilis var. meyeriana Kuntze; Jussiaea variabilis var. pilosa Kuntze; Ludwigia leptocarpa var. meyeriana (Kuntze) Alain) ?;     
   
USA (Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Kentucky,
Louisiana, Maryland, Missouri, Mississippi, North Carolina, Ohio, Oklahoma,
Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia),
Venezuela (Amazonas, Anzoategui, Apure, Barinas, Bolivar, Cojedes, Delta
Amacuro, Guarico, Miranda, Monagas, Nueva Esparta, Tachira, Yaracuy, Zulia),
N-Brazil (Para, Amazonas, Acre), Colombia (Amazonas, Antioquia, Atlntico,
Bolvar, Choc, Crdoba, Vaups, Vichada), NE-Brazil (Piaui, Ceara), WC-Brazil (Mato
Grosso, Goias, Distrito Federal, Mato Grosso do Sul), SE-Brazil (Minas Gerais,
Espirito Santo, Sao Paulo, Rio de Janeiro), Argentina (Chaco, Corrientes, Entre
Rios, Formosa, Misiones), S-Brazil (Rio Grande do Sul, Santa Catarina), Paraguay
(Caazapa, Central, Cordillera, Guaira, Pres. Hayes), Uruguay (Cerro Largo,
Rocha), Mexico (Campeche, Chiapas, Colima, Guerrero, Jalisco, Morelos, Nayarit,
Oaxaca, Puebla, Quintana Roo, San Luis Potosi, Sinaloa, Tabasco, Tamaulipas,
Veracruz, Yucatan), Guatemala, Honduras, El Salvador, Guyana, Surinam, French
Guiana, Costa Rica, Guianas, Galapagos Isl., Peru, Bolivia (Beni, Cochabamba, La
Paz, Pando, Santa Cruz), Nicaragua, Ecuador, Panama, Hispaniola, Jamaica, Puerto
Rico, Lesser Antilles (Barbados, Dominica, Grenada, Guadeloupe, Marie Galante,
Martinique, St. Lucia, St. Vincent), Madagascar, Mauritania, Senegal, Gambia,
Guinea-Bissau, Burkina Faso, Sierra Leone, Mali, Niger, Chad, Sudan, South
Sudan, Ethiopia, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, Central
African Republic, Gabon, Sao Tome, Congo (Brazzaville), D.R.Congo (Zaire),
Uganda, Kenya, Rwanda, Burundi, Angola, Zambia, Zimbabwe, Malawi, Mozambique,
South Africa (KwaZulu-Natal), Namibia, Botswana as per Catalogue of Life;

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Ludwigia Species for ID : Atlanta, Georgia : 14JAN19 : AK-22 : 9 posts by 3 authors. Attachments (3)

Seen near a water body in Atlanta during my visit in Oct,18.

For Species id please.

I believe it is Ludwigia hexapetila; non-native in Georgia, also found in Florida (as well as in the ditch in my front yard!). Thank you.
It is difficult to tell apart from L. grandiflora. Here are two links with detailed explanations.
https://plants.ifas.ufl.edu/wp-content/uploads/files/caip/pdfs/LudwigiaHexapetala-fromAquaticsSpring2014.pdf
https://plants.ifas.ufl.edu/plant-directory/ludwigia-hexapetala/

Please, also look at Ludwigia leptocarpa.

Thanks. I will check for both suggested ids.

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Adding another picture which is better. Hope it helps.

Attachments (1)

Thank you for the additional and most excellent photo.
There are several scientific papers that explain the difficulty in differentiating between Ludiwigia grandiflora and L. hexipetala.
One would need to measure the petal length, the sepal length and look at the chromosomes.
One a hexaploid and one is a decaploid.
http://www.guynesom.com/Ludwigiagrandiflora.pdf

To add to the confusion, there are also naturally-occurring hybrids of the two.
This link leads to an explanation of how closely we must look to identify Ludiwigia while in the field:
https://plants.ifas.ufl.edu/wp-content/uploads/files/caip/pdfs/LudwigiaIDGuide.pdf