Ludwigia sedioides -- Center for Aquatic and Invasive Plants
Non-Native in Florida
This species appears on the following legally prohibited plant lists
Ludwigia sedioides, commonly known as Mosaic flower, is a herbaceous perennial plant of the family Onagraceae. It has yellow flowers that bloom from June to August. Native to Brazil and Venezuela, its habitat includes wet, swampy localities.
Source: Wikipedia Ludwigia sedioides
This species is popular in the pond plant trade where it is advertised as "great for surface coverage" and "spreads quickly".