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Eichhornia crassipes:
Water hyacinth
Eichhornia crassipes (Mart.) Solms: Water hyacinth. Pontederiaceae (pickerelweed family).
Exotic perennial. Forms extensive, dense, floating mats of robust plants interconnected by spongy stolons. Plants can reach up to 3.3 ft (1 m) in height but are usually found at 9 - 12 in (22.5 - 30 cm) tall. The numerous roots with their large stout root hairs are easily seen by pulling a plant out of the water; these roots do not anchor in the substrate. The leaf blade is short, leathery, broadly oval to circular, and parallel-veined; it is held upright on a spongy leaf stem with a swollen to bulbous midsection that gives the plant buoyancy. Showy clusters of orchid-like lavender flowers are held above the water on stout stalks; the flower has a yellow dot in the upper petal. Stem runners or stolons emerge from plants at the water surface and generate daughter plants that multiply in turn. Rapid vegetative reproduction and its impenetrably dense biomass make this species a major noxious weed. It destroys native aquatic habitat and interferes with all water uses. Although plants may be used as livestock forage or compost, and have provided fiber material in the tropics, water hyacinth has nuisance status everywhere it has been introduced. When comparing this plant with Limnobium spongia, note the showy purple flower, swollen leaf stalks, and absence of spongy cells on the underside of the leaf in water hyacinth.
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