ABSTRACT
A Brazilian, Karl F. P. Martius, was the first naturalist to describe the plant that has come to be known as "the world's worst weed" and the "million dollar weed," the floating aquatic plant commonly called the water hyacinth. The immediately discernible effects of water surfaces being covered by water hyacinths to some extent can be expressed as quantitatively measurable economic losses, or, conversely, by estimates of economic benefits derived from removal of the growths. This is true mainly for agriculture, navigation, water management, wildlife conservation, and commercial fishing, but also applies to the recreational activities of boating, swimming, sport fishing, and hunting. The principal areas affected by water hyacinth and alligator weed are regions of heavy total annual rainfall. However, the precipitation pattern is irregular so that water management is necessary to prevent floods and to conserve impounded water for use during prolonged dry periods.
