In this book, Part III "Aquatic Angiosperms", the author has described the flowering plants living in water, rooted in the soil and leaves and flowers present above the water level, or totally submerged in water. The parts of the plants have been examined and drawn by the author, who has travelled almost throughout Tamil Nadu. As a teacher of over 30 years in Botany, Annamalai University, he has the experience of 25 years as Botanic Garden in-charge, in Annamalai University. Besides guiding Ph. D and M. Phil Scholars in Cytotaxonomy and Cytogenetics (30 Ph. D and 46 M. Phil), he has also published research papers in most of the families of flowering plants in cytotaxonomy, cytogenetics and chemotaxonomy in Advanced Journals. This book is the continuation of the previous book of the author on Flowering plants of Tamil Nadu, Part I II Mangrove Flora and Marine Angiosperms. More important plants, their uses, frequency of occurrence and the importance of taking conservation measures are provided in this book.