Ludwigia palustris is a species of flowering plant in the evening primrose family known by the common names marsh seedbox,[1] Hampshire-purslane[2] and water purslane.

This is an aquatic or semiaquatic perennial herb which grows in moist to wet to flooded areas.

The species epithet palustris is Latin for "of the marsh" and indicates its common habitat.

[3] The plant can be highly invasive outside its native range, very adaptable, and reproduces asexually.

[4] Ludwigia palustris poses a potential threat to wetland vegetation in Victoria, Australia.