Pontederia crassipes - Water Hyacinth

Water hyacinth is a free-floating perennial aquatic plant native to tropical and sub-tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in height. The leaves are 10-20 cm across, and float above the water surface. They have long, spongy and bulbous stalks. The feathery, freely hanging roots are purple-black. An erect stalk supports a single spike of 8-15 prominently attractive flowers, mostly lavender to pink in colour with six petals. One petal bears a yellow spot. One of the fastest growing plants known, water hyacinth reproduces primarily by way of runners or stolons, which eventually form daughter plants. Each plant can produce thousands of seeds each year, and these seeds can remain viable for more than 28 years. Water hyacinth are vigorous growers known to double their population in two weeks. Water Hyacinth was introduced as an ornamental plant, but has become a weed throughout the world, including India. It is also found in East Himalaya.