Pontederia crassipes

Pontederia crassipes (formerly Eichhornia crassipes), commonly known as common water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range. It is the sole species of the subgenus Oshunae within the genus Pontederia. Anecdotally, it is known as the "terror of Bengal" due to its invasive growth tendencies. Water hyacinth is a free-floating perennial aquatic plant (or hydrophyte) native to tropical and subtropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as in height. The leaves are across on a stem, which is floating by means of buoyant bulb-like nodules at its base above the water surface. They have long, spongy, bulbous stalks. The feathery, freely hanging roots are purple-black. An erect stalk supports a single spike of 8–15 conspicuously attractive flowers, mostly lavender to pink in colour with six petals. When not in bloom, water hyacinth may be mistaken for frog's-bit (Limnobium spongia) or Amazon frogbit (Limnobium laevigatum). One of the fastest-growing plants known, water hyacinth reproduces primarily by way of runners or stolons, which eventually form daughter plants. Each plant additionally can produce thousands of seeds each year, and these seeds can remain viable for more than 28 years. Common water hyacinths (Pontederia crassipes) are vigorous growers and mats can double in size in one to two weeks. In terms of plant count rather than size, they are said to multiply by more than a hundredfold in number, in a matter of 23 days. In their native range, these flowers are pollinated by long-tongued bees, and they can reproduce both sexually and clonally. The invasiveness of the hyacinth is related to its ability to clone itself, and large patches are likely to all be part of the same genetic form. Water hyacinth has three flower morphs and is termed "tristylous". The flower morphs are named for the length of their pistils - long, medium, and short.