Pontederia crassipes (Water Hyacinth)

A floating aquatic perennial native to southern tropical America, Pontederia crassipes, or Water Hyacinth, belongs to the Pontederiaceae family. Its glossy, rounded leaves form rosettes and usually have swollen, spongy stalks that help the plant float. Long, feathery roots hang beneath the rosettes and become dark purple-black as they mature. The lilac flowers have an upper lobe marked with a violet blotch and yellow center. Horizontal stems connect new rosettes, allowing the plants to form dense floating mats. Introduced populations can obstruct waterways and reduce dissolved oxygen in the water. The species was formerly known as Eichhornia crassipes. Photographed in the department of Bolívar, Colombia.