This free-floating, rhizomatous, aquatic perennial is a native of South American rivers. The leaf is dark green, glossy and in a rossette with swollen petioles which are filled with spongy tissue called aerenchyma. The flower is showy and violet-pink. The attractive water hyacinth has been carried by tourists to over 80 countries around the globe during the past century. In the United States, it now clogs nearly two million acres of rivers and lakes. Florida, Louisiana and Texas--the states most affected by the water weed-- spend more than $10 million a year to limit the hyacinth's explosive growth. Ironically, however, not all Americans are trying to contain the plants. In fact, in some parts of the country, people are now intentionally growing hyacinths. The reason: the pestilential plant is capable of absorbing just about anything that dissolves in the water in which it lives--and that includes most kinds of pollution. As a result, some municipalities and businesses are now using hyacinths to clean up wastewater. The water hyacinth may be the most productive plant on earth. It can double its bulk in about two weeks. Under normal growing conditions, ten hyacinth plants can multiply to 600,000 and take over an acre of water in just eight months. As they grow, the plants mesh together to form a thick mat that can make a waterway impassable. In Malaya, mats of hyacinth once damed a river and caused flooding throughout the province of Kota Bharu.