flotant
A mass of floating vegetation, especially on the waters of the Mississippi delta.
... (flotants) occur in abandoned distributaries and throughout the upper Mississippi Delta Plain. Flotants can be found in 3 settings : 1) an active or "live" flotant of various ages. 2) a flotant that is being transgressed by marine[…]
Where it comes from
Old French flotant, (French flottant), present participle of floter (“to float”).
Adapted from the Wiktionary entry flotant (CC BY-SA 4.0).