Last Updated: Spring 2012
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Home Range/U.S. Introduction:
The native range of this species is unknown. It grows naturalized or natively in warm regions of the United States from Florida to Texas.
U.S. Range Map:
Distribution was determined by a combining of the distribution information obtained from the following websites:
USDA, NRCS. 2012. The PLANTS Database (http://plants.usda.gov, 18 June 2012). National Plant Data Team, Greensboro, NC 27401-4901 USA.
U.S. Geological Survey. . Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [6/18/2012].
Plants are free-floating herbs that form stolons. During dry seasons, some plants may be found rooted in wet soil. The leaves are sessile in a rosette, entire, cuneate to obovate-cuneate to about 25 cm long, strongly ribbed and densely pubescent and appearing gray-green. The veins are parallel. The inflorescence has both male and female flowers on a short stalk in the axils of leaves. Sepals and petals are absent. Fruits are many seeded, green berries.
Waterlettuce grows in lakes and in low velocity streams and canals (Tarver et al. 1986). Plants form many new plantlets on stolons. The seeds are dispersed by water.
The species is commonly weedy, forming dense mats and clogging waterways. A weevil and a moth, introduced for biological control of this species, have caused significant reductions in population sizes.
Tarver, D. P., J. A. Rogers, M. J. Mahler, and R. L. Lazor. 1986. Aquatic and Wetland Plants of Florida. Third Edition. Florida Department of Natural Resources, Tallahassee Florida.