The root system is not very well developed and root hair and root caps are absent. Some floating plants like the bladderwort are rootless while those like water lettuce and water hyacinth have a cluster or fibuicious roots.
The stem is in the form of a rhizome. It is soft and spongy containing air activities filled with gases. The gases also help to keep the plants afloat or in position under water. The epidermis is without the protective cuticle and is meant for absorption of water and not for protection.
The leaves of submerged plants are thin and narrow and the cuticle and stomata are absent. The leaves of floating plants have large broad leaves which have a thick cuticle and stomata on the upper surface. Exchange of gases for respiration and photosynthesis take place through the upper surface while water is absorbed through the lower.
Amphibious plants are plants that live in areas which are alternatively flooded or dried up. Examples of such plants are the water crowfoot, water plantain and arrowhead.
The submerged plants vallisneria, hydrilla and naias. The partly submerged ones are the water lily, lotus and giant water lily. The floating plants are the bladderwort, horwort, duckweed, water lettuce, water hyacinth and water chestnut.
