The Pontederiaceaefamily was classified in the Commelinalesorderin 2003. Thisfamily consists of heterostyled aquatic plantsin the tropical and subtropical regions of the world. The Heterostylia (used to evade self pollination) is a phenomenon seen in the structure of the flowers of some plantsstudied and described by Charles Darwin.
A well known memberof thefamilyis the Eichhornia Kunthgenus and the water hyacinth species (Eichhornia crassipes (Mart.) Solms.). The leaves are gathered in a rosette.In the base they have a protruded part of porous tissue thanks to which the plant stays on the water surface.The roots grow to half a meter of length and are entirely below water. The flower resembles a hyacinth. It is pink, blue or violet in color.
The plant propagates (spreads) quickly and in a short time covers the water surface. This hampers the movement even of vessels. The thick layer of plantsdeteriorates the oxygen content of the lake/river leading to a decrease of the other inhabitants.
The species was used for the first time by Belgian colonizers in Ruanda for the beautification of their mansions.From there it found its way into Lake Victoria where it was seen for the first time in 1988. As it has no natural enemies there it quickly propagatedand turned into an ecological bomb for the region. Stifling the water surface the plant causes the fish to diminish and harms local economy.