Utricularia inflata Walter

Common Name: Swollen bladderwort

Synonyms and Other Names:

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Identification: Submersed free-floating plant characterised by small bladders attached to stems that branch in a leaflike fashion. Yellow flowers are carried on tall stalks (scapes) held above the water by a whorl of inflated branches, resembling spokes of a wheel (Burks 1996; Rossbach 1939). Utricularia species are carnivorous in that the bladders trap and digest tiny animals, especially small crustaceans (Godfrey and Wooten 1981). Uticularia inflata is oftentimes confused with, yet morphologically distinct from, the smaller and more widespread U. radiata Small (U. inflata var. minor Chapman) (Reinert and Godfrey 1962).


Native Range: The Atlantic and Gulf coastal plains, extending from southern New Jersey to Florida and westward to eastern Texas and southeastern Oklahoma (Godfrey and Wooten 1981; Nelson and Couch 1985).

Means of Introduction: Located far from its natural range, there is little chance that Utricularia inflata was carried to western Washington by migrating waterfowl. More than likely it was liberated intentionally, either as an ornamental or by someone anticipating mosquito control. Waterfowl are suspected to be spreading the plant from lake to lake within the local region (K. Hamel pers. comm. 1998). Plants reproduce vegetatively and by seed.

Status: At a pioneering stage in western Washington where reports are increasing and its proliferation is considered a nuisance (WSDE 1998).  Considered a potential threat in Adirondack Park where its been found in a few waterbodies (Oles and Flint 2007).

Great Lakes Impacts:

Remarks: Floating Utricularia inflata is known to grow abundantly in its native range, especially in shallow waters, following drought or drawdown. Its competitiveness in the southern US is diminished by the fact that it's major growth period occurs in the late winter-early spring, and it is inactive during the the major summer growing season (Sanders and Mangrum 1973). This aspect could make U. inflata more competitive in the relatively cooler growing season of the Pacific Northwest.

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Author: Howard Morgan, V.

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Revision Date: 9/14/2011

Citation for this information:
Howard Morgan, V., 2023, Utricularia inflata Walter: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/GreatLakes/FactSheet.aspx?Species_ID=238, Revision Date: 9/14/2011, Access Date: 12/7/2023

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.