Disclaimer:

The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

---

Common name: parrot feather

Synonyms and Other Names: Brazilian watermilfoil, parrot’s feather, parrot-feather, parrotfeather, parrot feather watermilfoil, Enydria aquatica (Vell.), Myriophyllum brasiliense (Camb.), Myriophyllum proserpinacoides (Gillies ex Hook. and Arn.)

Taxonomy: available through www.itis.gov

Identification: Parrot feather (Myriophyllum aquaticum) is heterophyllous, meaning it has both an emergent and submersed leaf form. Emergent leaves are whorled, stiff, and usually have 20 or more linear divisions (10 leaflet pairs) on each leaf (Godfrey and Wooten 1981). The leaves appear feather-like and grayish green and can extend to 30 cm above the water surface.

The submersed shoots, similar to those of Eurasian watermilfoil (M. spicatum), are comprised of whorls of four to six filamentous, pectinate leaves, 1.5 to 3.5 cm long, arising from each node (Mason 1957, Washington State Department of Ecology 2011). Submersed leaves are reddish orange. When the submersed shoots reach the water surface, plant growth changes and begins to creep along the water surface with extensive branching from nodes followed by vertical growth of emergent stems (Moreira et al. 1999).

Small, white flowers occur in the leaf axils on the emergent shoots and are approximately 1/16 inch long (Washington State Department of Ecology 2011). Parrot feather lacks structures for storage, dispersal, and perennation (e.g., tubers, turions, and winter buds), and therefore stolons serve all these functions (Sytsma and Anderson 1993).

Size: leaves 1.5 to 5 cm, stems up to 5 feet.

Native Range: Myriophyllum aquaticum is a native of the Amazon River basin in South America, including Brazil, Bolivia, Ecuador, Peru, as well as Argentina, Chile, and Paraguay (Washington State Department of Ecology 2011). It prefers to inhabit subtropical regions (Fernandez et al. 1993).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Parrot feather grows well in shallow wetlands, slow moving streams, irrigation reservoirs or canals, edges of lakes, ponds, sloughs, or backwaters (Sutton 1985). Although it can grow in moist soil and tolerates a wide-range of water levels, parrot feather grows most rapidly in higher water levels (but has been documented in depths up to 16 ft; Banfield 2008) and high-nutrient environments (Hussner et al. 2009; Sutton 1985; Sytsma and Anderson 1993). Parrot feather requires rooting in bottom sediments, in habitats where light can penetrate to the bottom favor growth and colonization. Parrot feather thrives under slightly alkaline conditions (pH range 6.8-8.0), prefers temperatures between 16-23°C, and can withstand a water hardness level between 50-200 ppm (Federation of New Zealand Aquatic Societies, in Mabulu 2005). This species displays photosynthetic activity at pH levels of 6 to 8.5, depths of 0 to 10 meters, and temperatures from 10°C to 30°C, though it can survive even broader ranges (Robinson 2003; WIDNR 2011). It can also survive frequent inundation of salt water as long as concentrations remain below 4 ppt (Sutton 1985). Parrot feather is not seriously affected by frost (Moreira et al. 1999); however, a hard or extended period of frost may kill emergent shoots in northern latitudes (WIDNR 2011). Parrot feather can survive winters in its submersed form and begin growth when water temperatures reach 7°C (Moreira et al. 1999). Nevertheless, invasion tends to fail in areas with severe winters, because parrot feather does not store phosphorus or carbon in its rhizomes (Mabulu 2005).

Parrot feather is a dioecious species, however only pistillate (female) plants are found outside of South America. Staminate (male) plants are rare even in native populations of South America (Orchard 1981). For this reason, seed production is not known to occur (Aiken 1981) and reproduction is exclusively vegetative in North America (Orchard 1981). Reproduction occurs by fragmentation of emergent and/or submersed shoots, roots, rhizomes, or attached plant fragments (Center for Aquatic and Invasive Plants, UF/IFAS 2010; Les and Mehrhoff 1999; Mabulu 2005).

Parrot feather has an annual growth pattern, forming shoots in spring from overwintering rhizomes as water temperature increases. Rhizomes provide support for adventitious roots and buoyancy for emergent summer growth. Flowers usually appear in spring, or in fall for some plants. The plant usually dies back to its rhizomes in the autumn (Mabulu 2005).

Means of Introduction: Escaped ornamental pond plant.

Status: Established in North America.

Impact of Introduction:

Summary of species impacts derived from literature review. Click on an icon to find out more...

Ecological	Economic	Human Health	Other

Dense infestations can rapidly overtake small ponds and sloughs, impeding water flow resulting in increased flood duration and intensity. Parrotfeather may also out-compete more desirable native macrophytes. Little information exists on the direct impact that parrotfeather has on fish and wildlife. Dense beds of parrotfeather have resulted in reductions in dissolved oxygen in the water column, which may be detrimental to fish (Fonseca 1984 cited in Moreira et al. 1999). Parrotfeather growth can inhibit the growth of more desirable plant species such as pondweeds and coontail (Ferreira and Moreira 1994), which are readily utilized by waterfowl as food items (Wersal et al. 2005). A strong correlation was determined between the density of parrotfeather growth and the presence of mosquito eggs and larvae (Orr and Resh 1989), which may lead to increases in mosquito born diseases that could infect wildlife and humans.

Remarks:
 

References: (click for full references)

Aiken, S.G. 1981. A conspectus of Myriophyllum (Haloragaceae) in North America. Brittonia 33: 57-69.

Anderson, L.C. (curator). 2009. Herbarium Specimen Voucher Data, Florida State University (FSU), Herbarium. Florida State University, Tallahassee, FL. http://herbarium.bio.fsu.edu/.

Anderson, L.W.J. 1993. Aquatic weed problems and management in the western United States and Canada. Chapter 19a In: A.H. Pieterse and K.J. Murphy, eds. Aquatic Weeds, 2nd Edition. Oxford Scientific Press, Oxford, U.K. pp. 371-391.

Anderson, L.W.J., E. Chilton, A. Cofrancesco, E. Glenn, W.T. Haller. 1999. Report of the Salvinia molesta ("Giant Water Fern") Science Advisory Panel.

Aquatic Resources Education Center. 1995. List of Aquatic Plants found in Delaware Ponds 1973-1995. Division of Fish and Wildlife, Department of Natural Resources and Environmental Control, Smyrna, DE.

Banfield, S. 2008. Aquatic Vegetation Management Plan 2008-2012: Meserve Lake, Steuben County. Available http://www.aquaticenhancement.com/AES%20documents/Meserve%202008%20final3.pdf. Accessed 13 September 2011.

Beal, E.O., and J.W. Thieret. 1986. Aquatic and Wetland Plants of Kentucky. Kentucky State Nature Preserves Commission, Frankfort, KY.

Calflora. 2015. The Calflora Database. http://www.calflora.org/. Accessed on 12/04/2015.

California Department of Fish and Game. 2009. California Aquatic Non-native Organism Database (CANOD). California Department of Fish and Game, Office of Spill Prevention and Response. http://www.dfg.ca.gov/ospr/Science/about_canod.aspx. Created on 03/08/2011. Accessed on 07/20/2011.

Cardwell, A.J., D.W. Hawker, and M. Greenway. 2002. Metal accumulation in aquatic macrophytes from southeast Queensland, Australia. Chemosphere 48: 653-663.

Catarino, L.F., M.T. Ferreira, and I.S. Moreira. 1997. Preferences of grass carp for macrophytes in Iberian drainage channels. Journal of Aquatic Plant Management 36:79-83.

Center for Aquatic and Invasive Plants, University of Florida, IFAS. 2010. Myriophyllum aquaticum. http://plants.ifas.ufl.edu/plant-directory/myriophyllum-aquaticum/.

Central Hardwoods Invasive Plant Network. 2010. Joint Aquatic Invasive Species Survey, 2010. University of Georgia, Athens, GA. http://www.rtrcwma.org/chip-n/.

Chester, E.W., B.E. Wofford, and R. Kral. 1997. Atlas of Tennessee Vascular Plants Volume 2. Angiosperms: Dicots. Volume 2. Center for Field Biology, Austin University, Clarksville, TN.

Cilliers, C.J. 1999. Lysathia n.sp. (Coleoptera: Chrysomelidae), a host-specific beetle for control of the aquatic weed Myriohphyllum aquaticum (Haloragaceae) in South Africa. Hydrobiologia 415:271-276.

Cohen, A.N., and J.T. Carlton. 1995. Nonindigenous Aquatic Species in a United States Estuary, A Case Study of the Biological Invasions of the San Francisco Bay and Delta. A report for the United States Fish and Wildlife Service, Washington, DC and The National Sea Grant College Program Connecticut Sea Grant. http://nsgl.gso.uri.edu/conn/connt95002/connt95002full.pdf.

Conner, W., C. Sasser, and N. Barker. 1986. Floristics of the Barataria Basin Wetlands, Louisiana. Castanea 51(2):111-128.

Couch, R., and E. Nelson. 1986. Myriophyllum spicatum. Pages 8-18 in Proceedings, First International Symposium on Watermilfoil (Myriophyllum spicatum) and Related Haloragaceae Species. The Aquatic Plant Management Society, Vicksburg, Mississippi.

Couch, R., and E. Nelson. 1991. The exotic Myriophyllums of North America. Pages 5-11 in Proceedings of the National Conference on Enhancing the States' Lake Management Programs. U.S. Environmental Protection Agency. Washington, DC.

Delwiche, C.F. (curator). 2001. Herbarium Specimen Voucher Data, Norton Brown Herbarium (MARY). University of Maryland, College Park, MD. http://www.nbh.psla.umd.edu/.

Diggs, G.M., Jr., B.L. Lipscomb, and R.J. O'Kennon. 1999. Shinners and Mahler's Illustrated Flora of North Central Texas. Botanical Research Institute of Texas (BRIT), Fort Worth, Texas.

EDDMapS. 2015. Early detection and distribution mapping system. The University of Georgia - Center for Invasive Species and Ecosystem Health.

Edgell, R. 2011. DNR to treat four northeastern lakes for invasive plants this summer. Indiana Department of Natural Resources. Indianapolis, IN. http://www.in.gov/activecalendar_dnr/EventList.aspx?fromdate=1/1/2007&todate=9/30/2015&display=Month&type=public&eventidn=4181&view=EventDetails&information_id=8361. Created on 04/25/2011. Accessed on 09/03/2015.

Engineer Research and Development Center. 2007. Myriophyllum aquaticum (Vell.) Verdc. (Parrotfeather). In PMIS, Noxious and Nuisance Plant Management Information Systems. U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS. Available http://el.erdc.usace.army.mil/pmis/pmishelp.htm.

Feiler, U., I. Kirchesch, and P. Heininger. 2004. A new plant-based bioassay for aquatic sediments. Journal of Soils and Sediments 4(4): 261-266.

Fernández, O.A., D.L. Sutton, V.H. Lallana, M.R. Sabbatini, J.H. Irigoyen. 1993. Aquatic weed problems and management in South and Central America. In: A.H. Pieterse, K.J. Murphy, eds. Aquatic Weeds, 2nd Edition. Oxford University Press, Oxford, U.K. pp. 406-425.

GBIF. 2013. Global Biodiversity Information Facility (GBIF) Database. Global Biodiversity Information Facility. http://www.gbif.org/. Accessed on 05/01/2013.

Gibbons, J. 2011. The Connecticut Agricultural Extension Stattion Aquatic Plant Survey Program. http://ct.gov/caes/cwp/view.asp?a=2799&q=376972&caesNav=|.

Glomski, L. M., A. G. Poovey, and K. D. Getsinger. 2006. Effect of carfentrazone-ethyl on three aquatic macrophytes. Journal of Aquatic Plant Management 44:67-69.

Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States: Dicotyledons. University of Georgia Press, Athens, GA.

Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of the Southeastern United States: Dicotyledons. University of Georgia Press, Athens, GA.

Gray, C. J., J. D. Madsen, R. M. Wersal, and K. D. Getsinger. 2007. Eurasian watermilfoil and parrotfeather control using carfentrazone-ethyl. Journal of Aquatic Plant Management 45:43-46.

Great Lakes Panel on Aquatic Nuisance Species (GLPANS). 2008. Prohibited species in the Great Lakes Region. Report November 2008.

Guillarmod, A. J. 1977. Myriophyllum, an increasing water weed menace for South Africa. South African Journal of Science 73:89-90.

Helton, R.J., and L.H. Hartmann. 1996. Statewide Aquatic Vegetation Survey Summary, 1995 Report. Inland Fisheries Division, District 3-E, Jasper, Texas.

Hoagland, B.W., and R.L. Jones. 1992. Wetland and riparian flora of the Upper Green River Basin, south-central Kentucky. Transactions of the Kentucky Academy of Science 53(3-4):141-153.

Hofstra, D. E., P. D. Champion, and T. M. Dugdale. 2006. Herbicide trials for the control of parrotsfeather. Journal of Aquatic Plant Management 44:13-18.

Hough, M.T. 1983. New Jersey Wild Plants. Harmony Press, Harmony, NJ.

Huffman, J.M., and W.S. Judd. 1998. Vascular flora of Myakka River State Park, Sarasota and Manatee Counties, FL. Castanea 63(1):25-.

Hussner, A., C. Meyer, and J. Busch. 2009. The influence of water level and nutrient availability on growth and root system development of Myriophyllum aquaticum. Weed Research 49: 73-80.

Hussner, A., K. Van de Weyer, E.M. Gross, and S. Hilt. 2010. Comments on increasing number and abundance of non-indigenous aquatic macrophyte species in Germany. Weed Research 50: 519-526.

iDigBio. 2015. Integrated Digitized Biocollections (iDigBio). National Resource for Advancing Digitization of Biodiversity Collections (ADBC), Gainesville, FL. https://www.idigbio.org/. Accessed on 07/16/2015.

Illinois-Indiana Sea Grant (IISG). 2011. Sea Grant Database of Aquatic Species Regulations. Available http://www.iiseagrant.org/speciesregs/index1.asp?commonName=parrot%27s+feather. Accessed 25 October 2011.

iMapInvasives. 2012. iMapInvasives Oregon. The Nature Conservancy. http://www.imapinvasives.org/. Accessed on 04/09/2015.

IPANE. 2001. Invasive Plant Atlas of New England (IPANE) at the University of Connecticut online database. http://invasives.eeb.uconn.edu/ipane/.

Jones, Jr., S.B. 1975. Mississippi Flora. IV. Dicotyledon families with aquatic or wetland species. Gulf Research Reports 5(1):7-22.

Knauer, K., S. Mohr, and U. Feiler. 2008. Comparing growth development of Myriophyllum spp. in laboratory and field experiments for ecotoxicological testing. Environmental Science and Pollution Research 15: 322-331.

Lemke, D.E. 1989. Aquatic macrophytes of the Upper San Marcos River, Hays Co., Tesas. Southwestern Naturalist 34(2):289-291.

Les, D.H., and L.J. Mehrhoff. 1999. Introduction of nonindigenous aquatic vascular plants in southern New England: a historical perspective. Biological Invasions 1(2): 281-300.

Loyola University Chicago. 2013. Illinois Database of Aquatic Non-native Species. GISIN, Fort Collins, CO. http://gisin.org/cwis438/websites/GISINDirectory/Occurrence_Result.php?ProjectID=391&WebSiteID=4. Created on 05/13/2015. Accessed on 05/13/2015.

Mabulu, L.Y. 2005. Myriophyllum aquaticum (aquatic plant). Global Invasive Species Database. Available http://www.issg.org/database/species/ecology.asp?si=401&fr=1&sts=sss&lang=EN.

Madsen, J.D. 2010. Invasive Plant Atlas of the MidSouth. Geosystems Research Institute, Mississippi State University, Starkville, MS. http://www.gri.msstate.edu/ipams/.

Madsen, J.D., G. Ervin, V. Maddox, & C. Abbott. 2010. Invasive Plant Atlas of the MidSouth. Mississippi State University. http://www.gri.msstate.edu/research/ipams/contactinfo.php.

Marson, D., B. Cudmore, D.A.R. Drake, and N.E. Mandrak. 2009a. Summary of a survey of aquarium owners in Canada. Canadian Manuscript Report of Fisheries and Aquatic Sciences 2905: iv + 20 pp.

Marson, D., B. Cudmore, D.A.R. Drake, and N.E. Mandrak. 2009b. Summary of a survey of water garden owners in Canada. Canadian Manuscript Report of Fisheries and Aquatic Sciences. 2906: v + 23 pp.

Martin, C.C. 1999. Invasive species grant proposal, survey of aquatic vegetation in Delaware's public ponds. Department of Natural Resources & Environmental Control, Division of Fish & Wildlife, Smyrna, DE.

Mason, H.L. 1957. A Flora of the Marshes of California. Universtiy of California Press, Berkeley, CA.

Medina, V.F., S.L. Larson, A.E. Bergstedt, and S.C. McCutcheon. 2000. Phyto-removal of trinitrotoluene from water with batch kinetic studies. Water Resources 34(10): 2713-2722.

Mehrhoff, L. 1996. Hawaiian flowering plants checklist. The State Museum of Natural and Cultural History, Honolulu, HI. http://wwwbishophawaiiorg. Created on 03/12/1996.

Michigan State University. 2015. Midwest Invasive Species Information Network (MISIN). Michigan State University, East Lansing, MI. http://www.misin.msu.edu/browse/. Accessed on 12/04/2015.

Moreira, I., T. Ferreira, A. Monteiro, L. Catarino, and T. Vasconcelos. 1999. Aquatic weeds and their management in Portugal: insights and the international context. Hydrobiologia 415: 229-234.

Moreira, I, A. Monteira, and T. Ferreira. 1999. Biology and control of parrotfeather (Myriophyllum aquaticum) in Portugal. Ecology, Environment and Conservation 5:171-179.

Muenscher, W.G. 1944. Aquatic plants of the United States. Comstock Publishing Company, Ithaca, New York.

Nelson, E.N. and R.W. Couch. 1985. History of the introduction and distribution of Myriophyllum aquaticum in North America. Proceeding, 1st International Symposium on watermilfoil (Myriophyllum spicatum) and Related Haloragaceae Species. 23-24 July 1985. Vancouver, B.C. pp. 19-26.

Nwoko, C.O. 2010. Trends in phytoremediation of toxic elemental and organic pollutants. African Journal of Biotechnology 9(37): 6010-6016.

Ogden, J. 1974. The reproductive strategy of higher plants. II. The reproductive strategy of Tussilago farfara L. J. Ecol. 62: 291-324.

Orchard, A.E. 1981. A revision of South American Myriophyllum (Haloragaceae), and its repercussions on some Australian and North American species. Brunonia 4:27-65.

Oregon State University. 2016. Oregon Flora Project. Oregon State University, Corvallis, OR. http://www.oregonflora.org/atlas.php.

Orr, B.K. and V.H. Resh. 1989. Experimental test of the influence of aquatic macrophyte cover on the survival of Anopheles larvae.  Journal of the American Mosquito Control Association 5:579-585.

Orr, B.K., and V.H. Resh. 1992. Influence of Myriophyllum aquaticum cover on Anopheles mosquito abundance, oviposition, and larval microhabitat. Oecologia 90: 474-482.

Parsons, J. 1996. Aquatic Plant Technical Assistance Program: 1995 Acitivity Report. Washington State Dept of Ecology, Environmental Investigations and Laboratory Services Program, Olympia, WA.

Parsons, J. 2005. Annual Washington State Aquatic Plant Survey Database. Washington Department of Ecology . http://www.ecy.wa.gov/programs/eap/lakes/aquaticplants/index.html#annualsurvey.

Parsons, J. 2007. Washington Aquatic Plant Monitoring Database. Washington Department of Ecology, Lacey, WA. http://www.ecy.wa.gov/programs/eap/lakes/aquaticplants/index.html.

Pfauth, M., and M. Sytsma. 2005. Final Coastal Lakes Aquatic Plant Survey Report. Center for Lakes and Reservoirs, Portland State University. http://www.clr.pdx.edu/publications/files/CoastalLakes.05.pdf.

Pine, R.T. and W.J. Anderson. 1991. Plant preference of triploid grass carp. Journal of Aquatic Plant Management 29:80-82.

PLANTS Profile: Myriophyllum aquaticum. http://plants.usda.gov/java/nameSearch. Accessed 2 January 2011.

Polomski, R.F., M.D. Taylor, D.G. Bielenberg, W.C. Bridges, S.J. Klaine, and T. Whitwell. 2009. Nitrogen and phosphorus remediation by three floating aquatic macrophytes in greenhouse-based laboratory-scale subsurface constructed wetlands. Water, Air, & Soil Pollution 197: 223-232.

Quayyum, H.A., A.U. Mallik, and P.F. Lee. 1999. Allelopathic potential of aquatic plants associated with wild rice (Zizania palustris): I. Bioassay with plant and lake sediment samples. Journal of Chemical Ecology 25(1): 209-220.

Queensland Herbarium. 2002. Invasive naturalized plants in Southeast Queensland, ranked list. [Extracted from Batianoff, G.N. and D.W. Butler. 2002. Assessment of Invasive naturalized plants in south-east Queensland. Appendix. Plant Protection Quarterly 17:27-34.] Queensland Environmental Protection Agency, Queensland Herbarium, Queensland, Australia. Available http://www.derm.qld.gov.au/register/p00727aa.pdf.

Radford, A.E., H.E. Ahles, & C. Bell. 1968. Manual of the vascular flora of the Carolinas. The University of North Carolina Press, Chapel Hill, North Carolina .

Radford, A.E., H.E. Ahles, C.R. Bell, D.E. Rayner, C.A. Smith, and J. Townsend. 1997. South Carolina Plant Atlas. https://sites.google.com/site/sc0heritage0trust/.

Regents of the University of California. 2015. Jepsen online interchange for California floristics. University and Jepson Herbaria, University of California, Berkeley. http://ucjeps.berkeley.edu/interchange.html.

Rice, P.M. 2008. INVADERS Database System. Division of Biological Sciences, University of Montana, Missoula, MT 59812-4824. http://invader.dbs.umt.edu (accessed 28 April 2008).

Richardson, R.J., R.L. Roten, A.M. West, S.L. True, and A.P. Gardner. 2008. Response of selected aquatic invasive weeds to flumioxazin and carfentrazone-ethyl. Journal of Aquatic Plant Management 46:154-158.

Rixon, C.A.M., et al. 2005. Invasion risks posed by the aquarium trade and live fish markets on the Laurentian Great Lakes. Biodiversity and Conservation 14: 1365-1381.

Rosa, C.S., R.D. Antunes, R.A. Pitelli, and R.L.C.M. Pitelli. 2009. Comparative evaluation of water losses by evapotranspiration in mesocosms colonized by different aquatic weeds. Planta Daninha 27(3): 441-445.

Sebbatini, M.R., K.J. Murphy, and J.H. Irigoyen. 1998. Vegetation-environment relationships in irrigation channel systems of southern Argentina. Aquatic Botany 60:119-133.

Sheppard, A.W., R.H. Shaw, and R. Sforza. 2006. Top 20 environmental weeds for classical biological control in Europe: a review of opportunities, regulations, and other barriers to adoption. Weed Research 46: 93-117.

Simmons, M.P., D.M.E. Ware, and W.J. Hayden. 1995. The vascular flora of the Potomac River watershed of King George County, Virginia. Castanea 60(3):179-209.

Smith, E.B. 1988. An atlas and annotated list of the vascular plants of Arkansas. 2nd edition. University of Arkansas, Fayetteville, AR. www.csdl.tamu.edu/FLORA/arkansas.

Sutton, D.L. 1985. Biology and ecology of Myriophyllum aquaticum. Proceeding, 1st International Symposium on watermilfoil (Myriophyllum spicatum) and Related Haloragaceae Species. 23-24 July 1985. Vancouver, B.C. pp. 59-71.

Sytsma, M.D. and L.W.J. Anderson. 1993. Biomass, nitrogen, and phosphorus allocation in parrotfeather (Myriophyllum aquaticum). Journal of Aquatic Plant Management 31:244-248.

Sytsma, M.D., J.R. Cordell, J.W. Chapman, and R.C. Draheim. 2004. Lower Columbia River Aquatic Nonindigenous Species Survey 2001-2004. Final Technical Report: Appendices. United States Coast Guard and the Unites States Fish and Wildlife Service. http://www.clr.pdx.edu/docs/LCRANSFinalReportAppendices.pdf.

Teles, A.N., and A.R. Pinto da Silva. 1975. A “pinheirinha” (Myriophyllum aquaticum (Vell.) Verde), uma agressiva infestante aquática. Agronomia lusitania 36: 307-323.

Texas Invasive Plant and Pest Council. 2015. Texas Invasives Database. http://www.texasinvasives.org/. Accessed on 11/20/2015.

Thomas, R.D., and C.M. Allen. 1998. Atlas of the Vascular Flora of Louisiana Volume III: Dicotyledons Fabaceae - Zygophyllaceae. Volume 3. Bourque Printing, Inc Baton Rouge, LA.

Toft, J.D., J.R. Cordell, and W.C. Fields. 2002. New records of crustaceans (Amphipoda, Isopoda) in the Sacramento/San Joaquin Delta, California, and application of criteria for introduced species. Journal of Crustacean Biology 22(1):190-200.

USDA, NRCS. 1997. The PLANTS database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, Louisiana 70874-4490. http://plants.usda.gov.

U.S. EPA. 2008. Predicting future introductions of nonindigenous species to the Great Lakes. NCEA, Washington, DC. Available http://www.epa.gov/ncea.

University of Florida Herbarium. 2016. Florida Museum of Natural History. University of Florida, Gainesville, FL. http://www.flmnh.ufl.edu/herbarium/.

Washington State Department of Ecology. 2008. Aquatic Plant Monitoring: Sloughs near Long Beach. http://www.ecy.wa.gov/apps/watersheds/aquaticplants/lakereport.asp.?=230.

Washington State Department of Ecology. 2011. Non-native invasive freshwater plants: Parrotfeather (Myriophyllum aquaticum), Technical Information. Washington State Department of Ecology, Olympia, WA. Available http://www.ecy.wa.gov/programs/wq/plants/weeds/aqua003.html.

Wersal, R.M., B.R. McMillan, and J.D. Madsen. 2005. Food habits of dabbling ducks during fall migration in a prairie pothole system, Heron Lake, Minnesota. Canadian Field Naturalist 119:546-550.

Wersal, R.M., J.D. Madsen, and M.L. Tagert. 2006. Aquatic plant survey of Ross Barnett Reservoir for 2005. Geosystems Research Institute.

Wersal, R.M. and J.D. Madsen. 2007. Comparison of Imazapyr and Imazamox for Control of Parrotfeather (Myriophyllum aquaticum (Vell.) Verdc.). Journal of Aquatic Plant Management 45:132-136.

Wersal, R.M. and J.D. Madsen. 2010. Comparison of subsurface and foliar herbicide applications for control of parrotfeather (Myriophyllum aquaticum). Invasive Plant Science and Management 3:262-267.

Wersal, R.M., and J.D. Madsen. 2011. Influences of water column nutrient loading on growth characteristics of the invasive aquatic macrophyte Myriophyllum aquaticum (Vell.) Verdc. Hydrobiologia 665: 93-105.

Westerdahl, H. E. and K. D. Getsinger. 1988. Aquatic Plant Identification and Herbicide Use Guide; Vol II: Aquatic Plants and Susceptibility to Herbicides. Technical Report A-88-9, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.

Wisconsin Department of Natural Resources (WIDNR). 2011. Aquatic Invasive Species Literature Review. Available http://dnr.wi.gov/invasives/classification/pdfs/Myriophyllum%20aquaticum.pdf. Accessed 25 October 2011.

Xie, D., D. Yu, L. Yu, and C. Liu. 2010. Asexual propagations of introduced exotic macrophytes Elodea nuttallii, Myriophyllum aquaticum, and M. propinquum are improved by nutrient-rich sediments in China. Hydrobiologia 655: 37-47.

Other Resources:
UF/IFAS Center for Aquatic and Invasive Plants - Myriophyllum aquaticum

ISSG Database: Myriophyllum aquaticum

State of Washington Department of Ecology

US Fish and Wildlife Service Ecological Risk Screening Summary for Myriophyllum aquaticum

Author: Wersal, R.M., E. Baker, J. Larson, K. Dettloff, A.J. Fusaro, and J. Redinger

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.