aquatic plants, completely or mostly submerged in water (in contrast to hydrophytes, whose lower part only is submerged in water).
Some hydatophytes are not attached to the ground by their roots (duckweed and Canadian pondweed), and others (the waterlily) are attached. Hydatophytes are classified according to their course of development. True hydatophytes are plants submerged in water, and their growth and development occurs only in water (some species of Ceratophyllaceae). Submerged aerohydatophytes are plants totally submerged in water; their growth occurs in water, but the pollination of their flowers takes place above water (spiral wild celery). Floating aerohydatophytes are plants a part of whose leaves and stems is immersed in water and the other part of which floats. The pollination of their flowers occurs above water. Many hydatophytes turn into peat.