What is the difference between Partially submerged, and Free floating aquatic plants.

Submergent plants are totally submerged, with all parts growing under water. Floating plants are not rooted like emergent or submergent plants. They float along the water's surface instead.

Emergents are plants that grow with the roots and some portions of the stems and foliage partially submerged in water; the plants' upper portions are visible above the water. Submergent plants are totally submerged, with all parts growing under water. Floating plants are not rooted like emergent or submergent plants.