One note:
Water Lettuce is prohibited, regulated or illegal in many US states:
Water Lettuce (Pistia stratiotes) - AL, CA, FL, LA, MS, SC, TX, WI
Water Lettuce Rosette (Pistia Rosette) - AL, CA, FL, LA, MS, SC, TX, WI
Water Lettuce Curly Leaf Rosette (Pistia Rosette) - AL, CA, FL, LA, MS, SC...