ABSTRACT
Floating aquatic plants, such as water hyacinth, water lettuce, and water fern were observed in large numbers in 1969 in many different locations in the Lower Mekong River Basin. Plants of this type tend to form mats and bogs of intertwined vegetation which are substantially denser than the growth of the individual species. Studies involving technical problems relating to flood control, hydroelectric power production, and water resources development of the Lower Mekong River Basin were begun in 1951 by the United Nations Economic Commission for Asia and the Far East. The climate of the project area is tropical monsoon. The soils of the Vientiane Plain and adjacent areas of northeast Thailand are light brown alluvial deposits of fine sandy silt and clay, fairly well suited to rice culture. Submersed aquatic plants are thin stemmed and profusely branched, and most are capable of rapid vegetative propagation from stem nodes, lateral buds, and stolons, as well as by fruits and seeds.
