Common Water Hyacinth (Eichhornia crassipes, Mart.)
Photograph by flora-on
Origin: Tropical South America
Size: very variable in size (can reach 1 m in height)
The Common Water Hyacinth is a floating fresh water perennial herbaceous plant. The first leaves are elongated and strap-like; the following leaves have spathulate form, are thick, glossy and aerial. The plant system consists of individual shoots with up to ten leaves arranged spirally; roots develop at the base of each leaf and form a dense mass. Axillary buds, develop as stolons, growing horizontal and origin daughter plats. The inflorescence is a spike with several blue/purple flowers; the fruit, a capsule, has numerous small seeds (up to 450).
Photograph by wikipedia
This species is native to tropical South America growing in freshwater lakes or rivers, enriched with plant nutrients, can also grow in flooded rice fields; can tolerate short periods at freezing but the optimum temperature of growing is 25° to 30° C. Grows extremely rapidly and can double its population size in 6 to 18 days. Has been widely introduced in North America, Europe, Asia, Australia and New Zealand where it is considered an invasive species.
The Common Water Hyacinth has been widely planted as ‘ornamental’ around the world, grows and reproduces quickly and competes with native aquatic plants; can absorb large amounts of heavy metals and after death will rot and sink to the bottom of the water causing secondary pollution. This species can completely cover water surfaces and cause it to dry out, it also affects human activities, like fishing and water transport.