Scientific Name: Pistia stratiotes
Common Names: Water Lettuce, Water-lettuce
Growth Habit: Herb/Forb
Hawaii Native Status: Introduced. This naturalized ornamental water garden plant is native to tropical America, but it is now a pan-tropical water weed.
Flower Color: Inconspicuous (white, pale green)
Height: Up to 8 inches (20 cm) tall, but usually less
Description: The tiny flowers have a white to pale green spathe and are followed by small, green, berrylike fruit. The leaves are whorled in small, lettuce-like rosettes that float on the surface of the water. The leaf blades are pale green, spongy, velvety-hairy, lined with indented parallel veins, sessile, wedge-shaped, and waterproof (water beads up and slides off of them). The roots dangle in the water and are up to 20 inches (50 cm) long. The plants usually propagate by stolons (creeping stems bearing cloned new plants).
These weedy aquatic plants can completely take over ponds, marshes, and slow-moving streams and canals, choking out native aquatic plants and disrupting the aquatic ecosystem.
Poisonous – The plants contain needle-like calcium oxalate crystals that can cause intense mouth burning and swelling along with gastrointestinal upset if ingested. These plants also absorb toxic metals from the water.
Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Liliopsida – Monocotyledons
Family: Araceae – Arum family
Genus: Pistia L. – pistia
Species: Pistia stratiotes L. – water lettuce
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