The Water Hyacinth obtains its bouyancy from swollen leaf stalks containing a type of natural air-filled foam. Notice those plants that grow on the edge of the pool in the mud no longer have these 'floats'. This species is a serious weed of inland tropical waterways.

The Water Lettuce (Pistia stratiotes) floats due to air bubbles which cling to the wax covered hairs on the leaves. the roots hang down in the water to help keep the plant upright. Push these plants under the water yourself to see what happens.

The Papyrus is the tall reed to the left. The stems were used in ancient Egypt to make paper.