Common name: Cuban bulrush
Synonyms and Other Names: Oxycaryum cubense
Identification: Cuban bulrush is a floating, epiphytic perennial herb (sedge), with a slender, erect triangular stem that is 30 to 92 cm in height. Slender leaves form at the base of the stem and extend above the water surface (Godfrey 1979). The reddish runners form mass together or with the roots/rhizomes of other plants to form floating mats (tussocks; Mallison et al. 2001, Bryson 2008).
Multiple inflorescences, either umbellate (short flower stalks which spread from a common point) or monocephalous (a single flower head which is unbranched) depending on form, are produced at the apical portion of each stem. Inflorescences are comprised of one to thirteen spherical heads that are 1-2 cm in diameter. The inflorescence is surrounded by 2 to 6 long leaf-like bracts. Seeds are in the form of spiked, buoyant ale or red-brown achenes (small, dry one-seeded fruit), which form in the spring through fall (Godfrey 1979, Bryson 2008).
Size: Stems can range from 30 to 92 cm in height (Godfrey 1979).
Native Range: Cuban bulrush is native to South America and the West Indies.
Hydrologic Unit Codes (HUCs) Explained
Puerto Rico &
Interactive maps: Point Distribution Maps
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Cyperus blepharoleptos are found here.
Table last updated 9/16/2021
† Populations may not be currently present.
Ecology: Cuban bulrush is found in free-floating mats and rafts that vary greatly in size. This species commonly establishes in freshwater ditches, marshes, ponds, lakes, rivers, and swamps (Bryson 2008). It is unclear if this species requires other vegetation for establishment and mat formation, but it appears that the epiphytic form of Cuban bulrush prefers areas of dense floating aquatic vegetation.
Means of Introduction: Cuban bulrush was likely introduced via ship ballasts and by achenes ingested and transported by migratory birds (Bryson 2008). Once in drainage, Cuban bulrush floating islands (or tussocks; Mallison et al. 2001) or seeds (Markwith et al. 2014) can disperse the plant downstream.
Status: Cuban bulrush is widespread throughout tropical and subtropical areas of Africa and the Americas, but is currently established in only six states in the southeastern United States (Bryson 2008).
Impact of Introduction: Cuban bulrush is known to form large floating islands (tussocks) that have numerous economic and ecological impacts on the waterbody. The tussocks have been observed blocking boat launches and impede navigation and recreation within waterbodies (Mallison et al. 2001, Bryson et al. 2008) and accumulating along shorelines (Mallison et al. 2001). The tussocks can also exclude and shades out desirable submersed vegetation ( Mallison et al. 2001, Robles et al. 2007, Bryson et al. 1996, 2008). Cuban bulrush is thought to be able to compete with other emergent plants (water hyacinth, water lettuce, and mosquito ferns) due to its tall epiphytic growth habit (Tur 1971, Robles et al. 2007). Underneath the floating mats, water quality can rapidly degrade due to increased organic matter and low dissolved oxygen (Mallison et al. 2001).
References: (click for full references)
Bryson, C.T., V.L. Maddox, and R. Carter. 2008. Spread of Cuban club-rush (Oxycaryum cubense) in the Southeastern United States. Invasive Plant Science and Management 1:326-329.
Godfrey, R.K. and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States: Monocotyledons. Athens, GA: University of Georgia Press. 348 p.
Mallison, C.T., R. K. Stocker, and C. E. Cichra. 2001. Physical and vegetative characteristics of floating islands. Journal of Aquatic Plant Management. 39:107-111.
Markwith, S.H., Mezza, G., Kennard, S.N. and S.G. Bousquin. 2014. Intra-Floodplain seed dispersal limitation and wetland community restoration. Ecological Restoration 32(3):249-259.
Robles, W., Madsen, J.D., Maddox, V.L. and R.M. Wersal. 2007. The invasive status of giant salvinia and hydrilla in Mississippi. Proceedings of the 37th Annual Mississippi Water Resources Conference:109-113.
McLaurin, C.S., Wersal, R.M., and Daniel, W.M.
Revision Date: 8/26/2019
McLaurin, C.S., Wersal, R.M., and Daniel, W.M., 2021, Cyperus blepharoleptos Steud.: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2819, Revision Date: 8/26/2019, Access Date: 9/17/2021
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.