Common name: water spangles
Synonyms and Other Names: common salvinia, Salvinia auriculata auct. non Aubl., Salvinia rotundifolia auct. non Willd.
available through www.itis.gov
Identification: Free floating, rootless aquatic fern. Horizontal, branching rhizomes float just below the water surface and produce, at each node, two floating to emergent leaves, and a third, submersed leaf that is dissected into filaments. Floating leaves are orbicular to oval in shape, with heart shaped bases and rounded to notched tips. Leaf length ranges from 0.4 to 2.0 cm. Smaller, orbicular leaves lie flat on the water surface; larger leaves become elongated and fold upright on the midrib. Shade grown leaves remain broadly orbicular, and emerald green. Leaves grown in full sun become larger and elongated and often change from emerald green to rusty brown with maturity and senescence. The upper surfaces of floating leaves are uniformly covered with rows of white, bristly hairs. The stalks of each hair divide into four thin branches that are spreading and free at the tips. The branching hairs create a water repellent shield. Long chestnut colored hair coats the underside of floating leaves, the submersed filaments, buds and the rhizome.
Salvinia minima is believed to be a sterile species. It is not known to produce fertile spores and is postulated to be of hybrid origin (Schneller 1980). Regardless, sporocarps are common among the submersed leaves of large plants. Sporocarps are sacs, which enclose smaller sacs (sporangia) that are formed to hold microscopic spores. Shaped like small lemons (~1mm wide) sporocarps are attached in spirals along the main axis of the submersed filaments.
Identification Keys: Nauman 1993;Wunderlin 2000; Mickel and Beitel 1988; Stoltze 1983.
Native Range: Central and South America; common and wide-ranging from southern Mexico to northern Argentina and Brazil (Mickel ad Beitel 1988, Stolze 1983). De la Sota (1976) remarked that, in Argentina, the natural range of Salvinia minima could not be precisely determined due to its frequency in the watergarden and aquarium trade.
Interactive maps: Point Distribution Maps
Puerto Rico &
Introduced to Bermuda, Puerto Rico, Spain and North America (Weatherby 1937; Proctor 1989; Lawalree 1964; Jacono et al 2001). Salvinia minima (common salvinia) has been recorded since 1930, from over 690 locations in 89 freshwater drainage basins of across the south and southeastern states.
First found and documented with specimens in Florida's St. John's River (Small 1931) [Keeley s.n. (PH)]. Known by 1937 in scattered regions of peninsular Florida from Miami, Sarasota, Gainesville and Bradenton (Jacono et al. 2001) and increasing in distribution to 12 Florida drainage basins within the next 30 years. Found on the Florida Panhandle first in 1979 [Godfrey 77112 (FLAS)] and in a subdivision pond near Pensacola in 2004 [J.R. Burkhalter & J.F. Jordan 19344 (UWFP, USF)]. Nearly 70 years after it's first discovery, S. minima was recollected along Blue Spring Run, a tributary of the St. Johns River [Jacono 142 (FLAS)] and by 2002 it was widely distributed throughout most of the state. Photographed August in north central Florida during low water conditions at the Santa Fe River and the infamous River Styx (#1 and #2).
Found in Georgia where collections were made first made in 1936 in open marshes near Savannah [Correll 5422(GA, GH)]. By the early 1980's, populations were scattered across much of southern Georgia, entering Lake Seminole at both the Flint River and Chattahoochee arms (A. Gholson herbarium). New in Alabama in 1982, found in the Mobile Delta area [Reicke s.n. (UNA); Haynes and Jacono 2000)]. Just five years later, becoming common in creeks and bays of the Mobile-Tensaw Delta (Zolczynski and Eubanks 1990) where populations fluctuate from tremendous to minor as influenced by tropical storms and other weather events. Increasing in range, as Hydrilla verticillata slows the natural flow of water in small tidal streams of the Mobile Delta (J. Zolcynski, pers. com.). Extending north to Auburn, east to Gantt Lake in the Upper Conecuh River Drainage [MacDonald 11217 (IBE, VDB) and most recently (2001-02) into the southwestern portion of Alabama where it has established at Coffeeville Reservoir and upstream, at Daub’s Swamp (J. Jernigan, pers. comm.).
First recorded in south-central Louisiana at canals along Chatsworth Levee, St. Mary Parish (Landry 1981), in the lower Bayou Teche drainage and becoming well distributed within the next ten years throughout coastal Louisiana by way of the Gulf Intercoastal Waterway to cover approximately 4000 acres in seven drainage basins, including the extensive Atchafalaya Basin (Montz 1989). Persisting in Saline Lake, in Winn and Natchitoche Parish, where populations regularly rebound after winter declines. By the late 1990's, S. minima was known in the far eastern and western regions of the state (C. Dugas, pers. comm.) and was persisting in at nuisance levels in canals, trenasses and ponds in the swamps and low salinity marshes of coastal Louisiana, particularly noticeable along the US 90/I-49 highway corridor between Lafayette and New Orleans (K. Vincent, pers. comm.). Clogging outboards and impeding net casting; introduced to rice and crawfish farms through irrigation practices. Found in 2007 in Lake Cheniere, where yearly drawdown and introduction of biocontrol agents may keep the population in check.
Believed carried to J.D. Murphree Wildlife Management Area, southeastern Texas, from Louisiana, on a marsh buggy during geologic exploration (Hatch 1995; R. Helton, pers. comm.) and found spreading to most major waterways in coastal Jefferson County in 1993. Soon extending inland to reservoirs and tributaries, notably B.A. Steinhagen Reservoir, on the lower Neches River, Sam Rayburn Reservoir, on the Angelina River, and Cow Bayou, on the lower Sabine River (L. Hartmann, R. Helton and C. D’Arbonne, pers. comm.) The most northern Texas infestation discovered in Wichita Falls (M. Howell, pers. comm.) and by 2001, infestations were dominating bayous and waterways south of I-10 in Orange and Jefferson counties (R. Helton, pers. comm.).
Reported from Bass Lake, just west of Great Swamp, South Carolina in 1999, but likely established there a number of years earliers [S. deKozlowski, pers. comm.; Jacono 118 (USCH)]. A population of Salvinia minima was found in a golf course pond on Daniel Island, Charleston County, in 2002. No plants were found when the site was revisited in July 2004, so the status of this population remains unknown. This site is surrounded by waters with salinity levels that would be lethal to Salvinia species, so it is likely that this population was eradicated by nature (J. Whetstone, pers. comm.). Also reported from Calhoun County, but doucmentation not available (J. Townsend, pers. comm.).
Mississippi's first population found in 1999 - collected at a tributary of the Upper Leaf River, Hattiesburg, where a recently created, landscaped lake is suspected as the source of introduction [Schweizer s.n. (IBE)]. In 2002, attention catching infestations were discovered at the Stennis Space Center, off the southern Pearl River in a canal used to transport rocket engines and fuel to test stands (Lorio s.n. FLAS) and farther west, at St. Catherine Creek National Wildlife Refuge, in Lake Gilliard, a shallow, 650 acre impoundment that receives annual flooding from the Mississippi River (L. Hartmann, pers. comm.). In 2004, a huge population was found along the northeastern margion of Lake Tangipahoa, located within the Percy Quin State Park, Pike County and surveys conducted by Mississippi Department of Wildlife, Fisheries and Parks found new infestations in Aberdeen and Columbus Lakes along the Tennessee-Tombigbee Waterway (L. Pugh & D. Riecke, pers. comm.).
Arkansas is home to the most northern U.S. occurrences (34º 30’ N) of S. minima, where populations persist through an exceptionally mild winter at several locals in the Bayou Meto drainage of east-central Arkansas (Peck 1999).
Waif populations: A specimen collected in 1994 from Aggie Pond, on the New Mexico State University campus [Roalson 764 (NMCR)] represents a non-persisting occurrence, as do undocumented records from southern New York, coastal Massachusetts, Maryland and Oklahoma.
Ecology: Reproduction and spread: The continuous branching and fragmentation of rhizomes turns out large volumes of vegetative daughter plants throughout the growing season. Copious hairy coverings minimize the desiccation of plants spotted on boats, trailers, alligators, turtles and even dogs leaving the water. Lateral buds deeply imbedded in the rhizome, may lie dormant during periods of reduced moisture and cold temperature. Small rhizome fragments, commonly sheltered in associating vegetation, provide material for reintroduction on the return of favorable growing conditions.
Habitat: Shallow backwaters of bayous, lakes and ponds, oxbows, ditches, slow flowing streams, cypress swamps and marshes.
Means of Introduction: Cultivated in greenhouses and gardens in the United States since the late 1880s (Weatherby 1921, 1937; Fernald 1950). Early plants in Florida likely entered natural areas from flooding of cultivated pools or through intentional release (Jacono et al 2001). Salvinia minima is still widely available in the water garden trade, either as a sale item or a contaminant. Although it continues to infest new regions, it is not included on the Federal Noxious Weed List and is prohibited only in the states of Texas and Louisiana.
Impact of Introduction: During earlier stages of colonization Salvinia minima demonstrates exponential growth rates (Gaudet, 1973), which may be just as high as those of Salvinia molesta.
In Texas and Louisiana, S. minima typically occurs in dense, expansive populations and is known as a very troublesome weed. At Lacassine Bayou, southwestern Louisiana, plants completely blanket a waterway measuring 19.3 km long and 110 m wide (Jacono et al 2001). Mats in Louisiana have been measured as thick as 20 - 25 cm (Montz 1989).
Clatworthy and Harper (1962) studied the competition among three species of duckweed, Spirodela polyrrhiza, Lemna gibba, Lemna minor and, the single temperate species of Salvinia, S. natans. In mixed cultures, they found that Lemna gibba and Salvinia natans were able to actually thrust aside Spirodela polyrhiza and Lemna minor. On the other hand, Lemna minor and Spirodela polyrrhiza coexisted without dominating each other. The authors correlated success in competition not with growth rate in pure culture, but rather with morphological characteristics. The presence of aerenchyma in Lemna gibba and the strong connecting rhizome between the fronds in Salvinia, as well as the stiff hairs of Salvinia, enabled these two species to ride over and displace the thinner, flat fronds of the others (reviewed in Landolt 1986). It should be noted that Salvinia natans is smaller and more delicate than S. minima.
An eight-year study at Jean Lafitte National Historic Park, Louisiana, found complete displacement of native Lemna species by Salvinia minima. (T. Doyle, LA, pers. comm.). The Lemnaceae (duckweeds) contain high protein content and are important food sources for waterfowl.
An investigation of competition among Salvinia minima, Spirodela [Landoltia] punctata (G.F.W. Mey.) C.H. Thompson and Azolla caroliniana Willdenow in north Florida found Salvinia minima dominating during the summer months (Dickinson and Miller 1998). Later in the season, S. minima was impacted by flooding and freezing and Spirodela punctata became the most abundant species (Dickinson and Miller 1998). Also introduced to North America, Spirodela punctata shows greater cold tolerance than Salvinia minima by extending to more northern temperate latitudes (Landolt 1986).
Like Salvinia molesta, S. minima is vulnerable to conditions of salinity. Biologists along the coast of southeastern Texas find Salvinia minima in their coastal study sites only during wintertime, when freshwater outflow is high and salinity measurements decline to 4 – 7 ppt. They regularly control Salvinia minima, and improve waterfowl habitat, by opening gates to allow saline water from the Gulf of Mexico into the bayous (Kirk Blood, Texas Parks and Wildlife Department, Port Arthur, Texas, pers. comm.).
During August, on the Waterhole Branch of the Fish River, Alabama, Salvinia minima was registered as growing well with surface water salinity levels at 4 –5 ppt. (Scott Phipps, Weeks Bay National Estuarine Research Reserve, AL, pers. comm.).
References: (click for full references)
de la Sota E.S. 1976. Sinopsis de las especies Argentinas del genero Salvinia
Adanson (Salviniaceae - Pteridophyta). (Synopsis of the Argentine species of the fern-genus Salvinia
Adanson(Salviniaceae).) Bol. Soc. Argent. Bot. 17. (1-2): 47 - 50.
Clatworthy, J.N. and J.L. Harper. 1962. Comparative biology of closely related species living in same area. 5. Inter- and intraspecific interference within cultures of Lemna spp. and Salvinia natans, J. Exp. Bot. 13:307–324.
Dickinson, M. B. & Miller, T. E. 1998. Competition among small, free-floating, aquatic plants. American Midland Naturalist, 140, 55–67.
Fernald, M.L., 1950. Gray’s Manual of Botany a handbook of the flowering plants and ferns of the central and northeastern United States and adjacent Canada. 8th (Centennial) ed. American Book Company, New York.
Haynes, R.R. and Jacono, C.C., 2000. Status of Salvinia (Salviniaceae) in Alabama. Castanea 65:225–227.
Jacono, C.C., Davern, T.R. and Center, T.D., 2001. The adventive status of Salvinia minima and S. molesta in the southern United States and the related distribution of the weevil Cyrtobagous salviniae. Castanea 66 (3):214–226.
Landolt, E. 1986. The family of Lemnaceae - a monographic study. Vol.1. In: Biosystematic investigations in the family of duckweeds (Lemnaceae). 2(71) :566.
Landry, G.P., 1981. Salvinia minima new to Louisiana. Amer. Fern J. 68:95.
Lawalree, A. 1964. Salviniaceae in Flora Europaea, vol. 1. In: Tutin, T.G. (Ed.), others with the assistance of P.W. Ball and A.O. Chater. University Press, Cambridge, pp. 24–25.
Mickel J.T. and Beitel J.M. 1988. Pteridophyte flora of Oaxaca, Mexico. ((Memoirs of the New York Botanical Garden, 46)). Bronx: New York Botanical Garden 568p.
Montz, G. N. 1989. Distribution of Salvinia minima in Louisiana. In Proc. 23rd Annual Meeting, Aquatic Plt Control Res Prog., 14-17 November 1988, West Palm Beach, FL, Misc. Paper A-89-1, USACOE, Waterways Experiment Station, Vicksburg, MS.:312-316.
Nauman C. E. 1993. Salviniaceae. Pp. 336–337, in Flora North America Editorial Committee. Flora of North America vol. 2. Pteridophytes and Gymnosperms. Oxford University Press, Oxford.
Proctor, G.R., 1989. Ferns of Puerto Rico and the Virgin Islands. Memoirs of the New York Botanical Garden, vol. 53. Bronx, New York.
Schneller J.J. 1980. Cytotaxonomic investigations of Salvinia herzogii de la Sota. Aquatic Bot. 9. (3): 279 - 283.
Small, J.K., 1931. Ferns of Florida: being descriptions of and notes on the fern-plants growing naturally in Florida (Illustrated). The Science Press, New York.
Stoltze, R.G., 1983. Ferns and fern allies of Guatemala. Part III. Marsileaceae, Salviniaceae, and the fern allies. Fieldiana Bot. 12:10–13.
Weatherby, C.A., 1921. Other records of Salvinia natans in the United States. Am. Fern J. 11 (2):50–53.
Weatherby, C.A., 1937. A further note on Salvinia. Am. Fern J. 27:98–102.
Wunderlin, R. P., B. F. Hansen and E. L. Bridges 1995. Atlas of Florida Vascular Plants. http://www.usf.edu.
Zolczynski, J., and Eubanks, M.J., 1990, Mobile delta submerged aquatic vegetation survey 1987: Mobile, Alabama Department of Conservation and Natural Resources and U.S. Army Corps of Engineers, Mobile District, 32 p.
Howard Morgan, V.
Revision Date: 9/14/2011
Howard Morgan, V., 2018, Salvinia minima Baker: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=297, Revision Date: 9/14/2011, Access Date: 2/23/2018
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.