Pistia stratoites
Synonyms: Apiospermum obcordatum, Pistia aegyptiaca, Pistia crispata, Pistia spathulata
Common names: water lettuce, water cabbage, Nile cabbage, shellflower
Pistia stratiotes (water lettuce) is a perennial floating freshwater aquatic plant in the family Araceae. Plants have thick, ribbed, stem-less leaves that are light green and hairy and are arranged radially, superficially resembling lettuce, both in size and structure. Water lettuce has long, fibrous roots connected to rosettes that hang down into the water vertically. Plants propagate mostly asexually by stolons and through fragmentation. Populations can expand rapidly in slow-moving or still water bodies, blocking movement and access to light and, in high nutrient conditions, creating hypoxic conditions that can kill other aquatic life. Pistia stratiotes can also serve as a breeding ground for mosquitoes. It is presumed to have a pantropical native distribution; in the United States, populations in Florida are considered native. Plants cannot tolerate frost and are therefore limited in their distribution to frostless, warm environments. Populations in California appear to be introduced from the southeastern United States. This species is banned from the ornamental aquatics trade in some regions and may have been introduced either (or both) by the ornamental trade or ballast water.
Cal-IPC Rating: Moderate — Alert?CDFA Rating: None?
Assessment(s)
Pistia stratoites Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
Weed Management Notes
No Weed RIC Management Notes are available for this species. Check for information on other species in the genus on the Weed RIC site.Cal-IPC Newsletter Articles
There are no newsletter articles associated with this species yet.
Cal-IPC Symposium Presentations
Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.
There are no Symposium presentations associated with this species yet.
Other Pistia stratoites Information
- Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.
- CalPhotos - Images of plants taken mostly in California.
- Calflora - Distribution map and records of this species in California.
- EDDMapS - Distribution of this species in North America.
- GBIF - Global distribution information.
- Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
- USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.