Any of about five species of aquatic plants that make up the genus Eichhornia of the pickerelweed family (Pontederiaceae).
They are native mainly to the New World tropics. Some species float in shallow water; others are rooted in muddy streambanks and lakeshores. All have slender rootstocks, feathery roots, rosettes of stalked leaves, and flowers arranged in spikes or clusters. The common water hyacinth ( E. crassipes ) is the most widespread. The leafstalk is spongy and inflated, and the upper lobes of its purple flowers have blue and yellow markings. It reproduces quickly, often clogging slow-flowing streams. It is used as an ornamental in outdoor pools and aquariums.
Common water hyacinth ( Eichhornia crassipes )
W.H. Hodge