Also called kariba weed.  An ♒︎ aquatic fern, part of family Salviniaceae.

Native to southeastern 🇧🇷 Brazil.  Invasive > Global Invasive > in USA+Canada Invasive > report it! Invasive > in USA Invasive > in Michigan prohibited in Michigan, incl. seeds, fragments and derivatives (.pdf)

Learn more about giant salvinia Salvinia molesta

Biological Control in Eastern USA (.pdf page 25)

Discover Life Encyclopedia of Life Google Google images USDA PLANTS db USGS Wikipedia