florida Early Detection Network


Fanwort, Carolina fanwort


Cabomba caroliniana Gray


Water-shield family


Cabomba caroliniana

Close-up of flower



Flower close-up


Synonyms: Cabomba caroliniana var. caroliniana Gray, C. aquatica DC. not Aubl., C. viridifolia Hort.


Botanical Glossary

Cabomba caroliniana is a submersed, rhizomatous, aquatic perennial that can have stems up to 2 m (6.5 ft.) long. It has two types of leaves. The petioled, submersed leaves are opposite, and sometimes whorled, peltate in form, and are 2-5 cm (0.75-2 in.) in width. These leaves are repeatedly divided into filiform segments. The small floating leaves are few and linear-elliptic in shape, have entire margins and often have a basal notch. These leaves are 6-20 mm (0.25-0.75 in.) long. The long-peduncled (3-10 cm (1.2-4 in.)) flowers are most often white with yellow at the center, but are rarely pink or purplish. The sepals and petals are about 1.25 cm (0.5 in.) across. The petals are auriculate at the their bases, and obovate in shape. The 3 ripened carpels are flask shaped. Page References Bailey 385, Crow & Hellquist 38, Fernald 642, Flora of North America 79, Gleason & Cronquist 46, Holmgren 44, Magee & Ahles 494. See reference section below for full citations.


Myriophyllum spp. (watermilfoils)*
Ranunculus aquatilis s.l. (water buttercup) Picture of R. aquatilis
Megalodonta beckii (Torr. ex Spreng.) Greene (Beck's watermarigold) Picture of M. beckii *See write-ups in the catalog of species for Myriophyllum spp. The leaves of Myriophyllum are whorled and the plants have small, axillary flowers. Ranunculus aquatilis has alternately arranged leaves as compared with the opposite arrangement of C. caroliniana. Megalodanta beckii has yellow, composite flowers and sessile leaves, while C. caroliniana has white flowers and petioled leaves.


This plant can be dispersed by seed but is more often spread by vegetative parts. These parts are spread by adhering to birds or boats, or by water currents.


Cabomba caroliniana is native to the southeastern part of the United States as well as some parts of South America. It is present from Florida to New Hampshire, west to Kansas, as well as Washington and Oregon. It has become invasive in other parts of the world such as India, Australia and Japan. In New England it is present in Connecticut, Rhode Island, Massachusetts and New Hampshire.


Considered native to the southeastern United States, Cabomba caroliniana was most likely introduced in the northern part of the country as an aquarium plant. It was either spread into New England by waterfowl, by pieces of the plants stuck onto boats, or by being washed downstream. The first northeastern report was from Hatfield, Massachusetts in 1930. In was reported from Rhode Island in 1936, and collected in Connnecticut since 1937.


Aquatic,Lake or Pond,River or Stream,Yard or Garden
Cabomba caroliniana prefers to lakes and ponds, but can also be found in slow-moving rivers and streams. It normally grows in 0.9-3 m (3-10 ft.) of water.


Cabomba caroliniana has the ability to form extremely dense stands and clog drainage systems. It also interferes with recreational activities such as swimming and boating. This plant is still sold in the aquarium trade, so it is often discarded in local waterbodies. The plants are able to root from vegetative parts and thus are easily spread. In the north it appears that the seeds do not readily germinate. However, viable shoots have been observed in January beneath ice.


Washington State Department of Ecology


Documentation required: Herbarium specimen or mounted snippet of the branch. Best time for documentation: Summer, fall.


Integrated Taxonomic Information System - Has general taxonomic information about the species.

The PLANTS Database - General information including a map

Washington State Department of Ecology - General information, including economic importance

The Connecticut River Homepage - Photographs and general information

University of Florida, Center for Aquatic and Invasive Plants - Photographs and general information

Texas Agricultural Extension Service- Aquaplant - Images and brief description


Bailey, L. H. 1949. Manual of Cultivated Plants. Macmillan, New York.

Britton, N. L. and A. Brown. 1970. An Illustrated Flora of the Northeastern United States vol. 2. Dover Publications Inc., New York.

Chambers, P.A., J.W. Barko, and C.S. Smith. 1993. Evaluation of invasions and declines of submersed aquatic macrophytes. Journal of Aquatic Plant Management 31: 218-220.

Crow, G.E. and C.B. Hellquist. 2000. Aquatic and Wetland Plants of Northeastern North America. Vol #. University of Wisconsin Press, Madison.

Fernald, M.L. 1950. Gray's Manual of Botany 8th edition. American Book Company, New York.

Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. Volume #3. Oxford University Press.

Gleason, H.A. and A.C. Cronquist. 1991. Manual of Vascular Plants of the Northeastern United States and Adjacent Canada. 2nd ed. New York Botanical Garden, Bronx, New York.

Holm, L.G., Pancho, J.V., Herberger, J.P., and Plucknett, D.L. 1979. A Geographical Atlas of World Weeds. John Wiley and Sons, New York, USA.

Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. New York Botanical Garden, Bronx, New York.

Ito, M. 1986. Studies in the floral morphology and anatomy of Nymphaeales III. Floral anatomy of Brasenia schreberi and Cabomba caroliniana. Botanical Magazine Tokyo 99 (1054): 169-184.

Les, D.H. and L.J. Mehrhoff. 1999. Introduction of nonindigenous aquatic vascular plants in southern New England: a historical perspective. Biological Invasions 1:281-300.

Mackey, A.P. and J.T. Swarbrick. 1997. The biology of Australian weeds. 32. Cabomba caroliniana Gray. Plant Protection Quarterly 12 (4): 154-165.

Magee, D.W and H.E. Ahles. 1999. Flora of the Northeast. University of Massachusetts Press, Amherst.

Riemer, D.N. and J.R. Trout. 1980. Effects of low concentrations of Terbutryne on Myriophyllum heterophyllum and Cabomba caroliniana. Journal of Aquatic Plant Management 18: 6-9.

Schneider, E.L. and J.M. Jeter. 1981. The floral biology of Cabomba caroliniana. Proceedings of the International Botanical Congress 13: 132.

Schneider, E.L. and J.M. Jeter. 1982. Morphological studies of the Nymphaeaceae 12. The floral biology of Cabomba caroliniana. American Journal of Botany 69 (9): 1410-1419.

USDA, NRCS. 2001. The PLANTS Database, Version 3.1. (//plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.