Wolffia otherwise known as Watermeal is the smallest flowering plant in the world
Watermeal feels like cornmeal to the touch. It is in the same family as Duckweed but much smaller and more course. Watermeal like duckweed is treated similiar. Using a flluridone compound is best. A combination of Diquat and Cutrine can be mixed to treat watermeal but this will only spot treat and it will come back. Using a Broad Spectrum herbicide will be more effective.