water hyacinth

A free-floating perennial aquatic plant (Eichhornia speciosa), native to South America, and introduced elsewhere; roots purple; leaves in rosettes, blade circular, stalk inflated and bladder-like; flowers c.4 cm/1½ in long, funnel-shaped, violet, in short dense inflorescence. It grows and spreads rapidly, blocks waterways, reservoirs, etc, and is probably the world's most troublesome aquatic weed. (Family: Pontederiaceae.)

The seven species of water hyacinths comprise the genus Eichhornia of free-floating perennial aquatic plants native to tropical South America.

Water Hyacinth as an invasive exotic plant

Water Hyacinths have been widely introduced throughout North America, Asia, Australia and Africa.