Overview

Brief Summary

History in the United States

Hydrilla first appeared in the Crystal River system of Florida in 1960. Imported by the aquarium trade, its presence on the Delmarva Peninsula was confirmed in 1981. It attracted national attention when infestations were found in the Potomac River in Washington, D.C. in the early 1980s. It is a federal noxious weed.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Comprehensive Description

Hydrilla verticillata (L. f.) Royle, 1839

Materials

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; stateProvince: Kachin; verbatimLocality: Tanaing Township; verbatimLatitude: 26° 22' 22'' N; verbatimLongitude: 96° 43' E; Event: eventDate: Sep. 15, 2005 ; Record Level: collectionID: MBK040056; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; stateProvince: Shan State; locality: Pindaya ; verbatimLatitude: 20° 59' 57" N; verbatimLongitude: 96° 39' 59" E; Record Level: collectionID: MBK080634; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Mandalay Division ; verbatimLatitude: 22° 00' 29'' N; verbatimLongitude: 96° 28' 06'' E; Event: eventDate: Jan. 11, 2002 ; Record Level: collectionID: Tanaka et al. 021712; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Mandalay Division ; verbatimLatitude: 20° 48' N; verbatimLongitude: 95° 15' E; Event: eventDate: Mar. 4, 2003 ; Record Level: collectionID: Tanaka et al. 028704; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Bago Division ; verbatimLatitude: 18° 42' 22'' N; verbatimLongitude: 95° 5' 59'' E; Event: eventDate: Dec. 9, 2006 ; Record Level: collectionID: Sugawara et al. 036433; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Kachin State ; verbatimLatitude: 26° 6' 34'' N; verbatimLongitude: 96° 42' 58'' E; Event: eventDate: Sep. 19, 2005 ; Record Level: collectionID: Tanaka et al. 040483; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Shan State ; verbatimLatitude: 20° 35' 41'' N; verbatimLongitude: 96° 31' 46'' E; Event: eventDate: Nov. 26, 2008 ; Record Level: collectionID: Tanaka et al. 080050; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Shan State ; verbatimLatitude: 20° 35' 41'' N; verbatimLongitude: 96° 31' 46'' E; Event: eventDate: Nov. 26, 2008 ; Record Level: collectionID: Tanaka et al. 080057; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Shan State ; verbatimLatitude: 20° 27' 28'' N; verbatimLongitude: 96° 50' 37'' E; Event: eventDate: Dec. 4, 2008 ; Record Level: collectionID: Tanaka et al. 080663; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Taunngyi ; verbatimLatitude: 20° 47' 14" N; verbatimLongitude: 97° 2' 7" E; Event: eventDate: Jan. 5, 1938 ; Record Level: collectionID: F.G. Dickason 9334; institutionCode: GH

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; locality: Chiang Mai Province; Chiang Dao District ; verbatimLatitude: 19° 28' 46" N; verbatimLongitude: 98° 54' 44" E; Event: eventDate: Dec. 11, 1992 ; Record Level: collectionID: V.A. Sunthorn, P. Palee 101; institutionCode: GH

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; verbatimLatitude: 13° 45' 10" N; verbatimLongitude: 100° 29' 45" E; Record Level: collectionID: T- 50413 [TI]; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; locality: Pha Team National Park, Ubon Ratchathani, Thailand ; verbatimLatitude: 15° 24' 07'' N; verbatimLongitude: 105° 29' 20'' E; Record Level: collectionID: Tr. Tanaka; institutionCode: TNS

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; locality: Hotel river Kwai, Kantchanabury ; verbatimLatitude: 14° 1' 59" N; verbatimLongitude: 99° 31' 10" E; Event: eventDate: Nov. 15, 2012 ; Record Level: collectionID: Y. Ito 1724; institutionCode: BKF

Distribution

Bangladesh, Bhutan, China (nationwide), Indonesia (nationwide), Japan, Malaysia (nationwide), Myanmar, Nepal, Pakistan, Papua New Guinea, Thailand, Sri Lanka.

  • Ito, Yu, Barfod, Anders S. (2014): An updated checklist of aquatic plants of Myanmar and Thailand. Biodiversity Data Journal 2, 1019: 1019-1019, URL:http://dx.doi.org/10.3897/BDJ.2.e1019
Public Domain

Plazi

Source: Plazi.org

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Hydrilla verticillata (L. f.) Royle, 1839

Materials

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; stateProvince: Kachin; verbatimLocality: Tanaing Township; verbatimLatitude: 26° 22' 22'' N; verbatimLongitude: 96° 43' E; Event: eventDate: Sep. 15, 2005 ; Record Level: collectionID: MBK040056; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; stateProvince: Shan State; locality: Pindaya ; verbatimLatitude: 20° 59' 57" N; verbatimLongitude: 96° 39' 59" E; Record Level: collectionID: MBK080634; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Mandalay Division ; verbatimLatitude: 22° 00' 29'' N; verbatimLongitude: 96° 28' 06'' E; Event: eventDate: Jan. 11, 2002 ; Record Level: collectionID: Tanaka et al. 021712; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Mandalay Division ; verbatimLatitude: 20° 48' N; verbatimLongitude: 95° 15' E; Event: eventDate: Mar. 4, 2003 ; Record Level: collectionID: Tanaka et al. 028704; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Bago Division ; verbatimLatitude: 18° 42' 22'' N; verbatimLongitude: 95° 5' 59'' E; Event: eventDate: Dec. 9, 2006 ; Record Level: collectionID: Sugawara et al. 036433; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Kachin State ; verbatimLatitude: 26° 6' 34'' N; verbatimLongitude: 96° 42' 58'' E; Event: eventDate: Sep. 19, 2005 ; Record Level: collectionID: Tanaka et al. 040483; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Shan State ; verbatimLatitude: 20° 35' 41'' N; verbatimLongitude: 96° 31' 46'' E; Event: eventDate: Nov. 26, 2008 ; Record Level: collectionID: Tanaka et al. 080050; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Shan State ; verbatimLatitude: 20° 35' 41'' N; verbatimLongitude: 96° 31' 46'' E; Event: eventDate: Nov. 26, 2008 ; Record Level: collectionID: Tanaka et al. 080057; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Shan State ; verbatimLatitude: 20° 27' 28'' N; verbatimLongitude: 96° 50' 37'' E; Event: eventDate: Dec. 4, 2008 ; Record Level: collectionID: Tanaka et al. 080663; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Myanmar ; locality: Taunngyi ; verbatimLatitude: 20° 47' 14" N; verbatimLongitude: 97° 2' 7" E; Event: eventDate: Jan. 5, 1938 ; Record Level: collectionID: F.G. Dickason 9334; institutionCode: GH

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; locality: Chiang Mai Province; Chiang Dao District ; verbatimLatitude: 19° 28' 46" N; verbatimLongitude: 98° 54' 44" E; Event: eventDate: Dec. 11, 1992 ; Record Level: collectionID: V.A. Sunthorn, P. Palee 101; institutionCode: GH

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; verbatimLatitude: 13° 45' 10" N; verbatimLongitude: 100° 29' 45" E; Record Level: collectionID: T- 50413 [TI]; institutionCode: TI

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; locality: Pha Team National Park, Ubon Ratchathani, Thailand ; verbatimLatitude: 15° 24' 07'' N; verbatimLongitude: 105° 29' 20'' E; Record Level: collectionID: Tr. Tanaka; institutionCode: TNS

Type status: Other material. Occurrence: recordedBy: Y. Ito ; Location: country: Thailand ; locality: Hotel river Kwai, Kantchanabury ; verbatimLatitude: 14° 1' 59" N; verbatimLongitude: 99° 31' 10" E; Event: eventDate: Nov. 15, 2012 ; Record Level: collectionID: Y. Ito 1724; institutionCode: BKF

Distribution

Bangladesh, Bhutan, China (nationwide), Indonesia (nationwide), Japan, Malaysia (nationwide), Myanmar, Nepal, Pakistan, Papua New Guinea, Thailand, Sri Lanka.

  • Ito, Yu, Barfod, Anders S. (2014): An updated checklist of aquatic plants of Myanmar and Thailand. Biodiversity Data Journal 2, 1019: 1019-1019, URL:http://dx.doi.org/10.3897/BDJ.2.e1019
Public Domain

Plazi

Source: Plazi.org

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

New York State Invasive Species Information

Background

Hydrilla (Hydrilla verticillata), also commonly called water thyme, is a submersed perennial herb. The plant is rooted in the bed of the waterbody and has long stems (up to 25 feet in length) that branch at the surface where growth becomes horizontal and forms dense mats. Small (2 - 4 mm wide, 6 - 20 mm long), pointed, often serrated leaves are arranged around the stem in whorls of 3 to 10. Southern populations are predominantly dioecious female (plants having only female flowers) that overwinter as perennials. Populations north of South Carolina, including populations in New York, are essentially monoecious (having both male and female flowers on the same plant) that set some fertile seed, and depend on tubers for overwintering. These monoecious plants produce female flowers with three translucent petals 10 - 50 mm long by 4 - 8 mm wide, and male flowers with three white to red narrow petals about 2 mm long.

Origin

The dioecious form of Hydrilla is believed to originate from the Indian subcontinent, specifically the island of Sri Lanka, although random DNA analysis also indicates India's southern mainland as a possible source location. The monoecious form is believed to have arrived on our shores from Korea.

Habitat

Hydrilla can be found infesting freshwater lakes, ponds, rivers, impoundments and canals.

Introduction & Spread

The dioecious strain of H. verticillata was imported as an aquarium plant in the early 1950s. Discarded (or intentionally planted ) colonies were found in canals in Miami and Tampa shortly after. The monoecious strain was introduced separately decades later in the Potomac Basin.

Both dioecious and monoecious Hydrilla propagate primarily by stem fragments, although turions (buds) and subterranean tubers also play an important role. The main means of introduction of Hydrilla is as castaway fragments on recreational boats and trailers and in their live wells. New colonies can often be found near boat ramps as such stem pieces become rooted in the substrate (even very, very small fragments can become the start of new populations). Boat traffic through established populations can shatter and spread Hydrilla throughout the waterbody, similar to the spread of Eurasian watermilfoil.

Hydrilla is often a contaminant on popular watergarden plants and may be unwittingly transported and established in private ponds in this manner. As with most invasive aquatic plant species, Hydrilla is a very opportunistic organism and can often be found taking over waters that have had populations of Eurasian watermilfoil chemically removed without a management plan for reestablishing native vegetation.

Impacts

Hydrilla can invade deep, dark waters where most native plants cannot grow. The plant’s aggressive growth (hydrilla’s 20 - 30 foot stems can add up to an inch per day) can spread into shallow water areas and form thick mats that block sunlight to native plants below, effectively displacing the native vegetation of a waterbody. Major colonies of hydrilla can alter the physical and chemical characteristics of lakes:

  • It is one of the world's worst aquatic invasive plants
  • It blocks sunlight and displaces native plants below with its thick, dense surface mats
  • Stratification of the water column and decreased dissolved oxygen levels can lead to fish kills
  • The weight and size of sportfish can be reduced when open water and natural vegetation are lost
  • Waterfowl feeding areas and fish spawning sites are eliminating by dense surface mats
  • Thick mats of vegation can obstruct boating, swimming and fishing
  • The value of shorefront property can be significantly reduced, hurting both homeowners and the communities that rely on taxation of shoreline property
  • In severe infestations, intakes at water treatment, power generation, and industrial facilities can be blocked.

Identification

Hydrilla has pointed, bright green leaves about 5/8 inches long. The leaves grow in whorls of 3 - 10 along the stem, 5 being most common. The margins of the leaves are serrated (toothed). Thin stalks from the stem end in a single, small, floating white flower at the water's surface. A key identifying feature is the presence of small (up to half inch long), dull-white to yellowish, potato-like tubers which grow 2 to 12 inches below the surface of the sediment at the ends of underground stems. These tubers form at the end of the growing season and serve to store food to allow Hydrilla to overwinter.

Native Lookalikes

Hydrilla is often confused with the common native water weed, Elodea Canadensis, which has whorls of 3 smooth-edged leaves as opposed to whorls of 4 to 10 serrated and spined leaves. Line art: University of Florida Center for Aquatic Plants.

Prevention

The best way to help prevent the spread of Hydrilla is to follow basic clean boating techniques:

For All Types of Watercraft:

- Be aware of and, if possible, avoid passing through dense beds of aquatic vegetation Inspect your watercraft, all equipment, and trailers after each use for any plant material

- Remove and dispose of all plant matter, dirt, mud and other material in a trash can or above the waterline on dry land well away from where it might get washed back into the lake

- Clean and dry all equipment thoroughly before visiting other water bodies (including anything that got wet, such as fishing gear and the family dog) For Non-Motorized Craft Such as rowing shells, canoes, kayaks, and sailboards:

- Open airlocks on shells or air bladders on kayaks after use and allow to dry thoroughly, as plant fragments can survive moist conditions for many days

Around Docks, Launch Sites, and Other Areas:

If plant fragments are piling up around dock areas, use a rake to remove plant material and dispose in the trash

Control

Mechanical harvesting and herbicide spraying are common control methods of controlling Hydrilla. Both are expensive and only moderately effective.

  • Power weed cutters mow underwater weeds below the water surface and gather them onto a conveyor. The harvesting process is expensive, costing over $1,000 per acre. Because of Hydrilla’s rapid growth, mechanical harvesting needs to be performed several times per growing season. Since the mowing and removal process cannot capture every single fragment of Hydrilla stem and leaf, water and wind currents moving away from the harvest area can easily carry these fragments to uninfested areas of a waterbody and result in new populations taking root.
  • Chemicals are easier to apply, but also costly. Herbicide spraying works best in small, enclosed bodies of water, and does not work at all in larger bodies the size of a Finger Lake, or in moving water such as a stream, river or canal. Herbicides can also have unintended impacts on native flora, as well. For those reasons, permits for chemical control of Hydrilla are difficult to obtain in New York.
  • Biological control insects as part of efforts to control Hydrilla have been attempted in Florida with mixed results. Leaf-mining flies from Australia and India and a tuber-feeding weevil from India have been used overseas. The insects released are not native to NY, nor are they currently permitted for release in the State. The use of non-native species to attempt to control another non-native species can be risky if the newly released species out-competes native insects, causing a new invasive species problem. The use of sterile grass carp has been used with some success in small lakes in the southern US but would be impractical in lakes the size of the Finger Lakes.
  • Another method of dealing with Hydrilla infestations is the control of water levels. Temporary control of Hydrilla has been shown to result from large-scale, long-term water drawdowns. However, since new plants can grow from the buried tubers, regrowth can take place when water levels are allowed to return to normal. Drawdowns also can have negative environmental impacts on native plant species and on fish populations.
  • Suction harvesting of Hydrilla growth by divers using very strong vacuum hoses can be used to remove Hydrilla from confined areas. However, as with drawdowns, if the underground tubers are not removed by dredging following the suction harvesting, regrowth can take place from the tubers during the next growing season. Further, any fragments that might escape during vacuum activities can float away to root and start new infestations.
  • The “best”, most effective way to control Hydrilla is the prevention of new Hydrilla infestations.

Eastern US Occurrences

Waterbodies infested with Hydrilla can be found in 70% of Florida's freshwater drainage basins, making it the most abundant aquatic plant in that state’s waters. Hydrilla is also widespread throughout Alabama; impoundments on the Tennessee River; eastern Mississippi; southeastern Tennessee; southwestern Georgia; South Carolina; eastern North Carolina; in Virginia’s Potomac, Rappahannock, and Appomattox Rivers and into the piedmont, in the tidal freshwater reaches of the Potomac River on the Virginia/Maryland border; along the western and northeastern shores of the Chesapeake Bay, including the Pautuxent River, where it is the most abundant plant species; Pennsylvania (in the Schuylkill River near downtown Philadelphia); eastern Kentucky; in ponds in Delaware; southeastern Connecticut; in a Cape Cod pond in Massachusetts; in southwestern Maine; in New Jersey’s Lower Delaware drainage; Indiana's Lake Manitou; Wisconsin; and since 2008, in three New York lakes in Suffolk and Orange Counties, and in Cayuga Lake in NY's Finger Lakes. Hydrilla can also be found at numerous sites west of the Mississippi River.

Cayuga Lake Inlet Infestation

H. verticillata was detected in the Cayuga Lake Inlet in Ithaca, New York in mid-August 2011 by staff of the Cayuga Lake Floating Classroom. A follow-up survey by Robert L. Johnson, a former researcher with the Cornell University Department of Ecology & Evolutionary Biology, now with Racine-Johnson Aquatic Ecologists, located extensive Hydrilla populations in several areas of the Inlet. As of early-September 2011, the Hydrilla appears to be localized to the Inlet, with no evidence of the plant in Cayuga Lake proper. This is the first detection of Hydrilla in upstate New York. The risk of the plant spreading to the rest of Cayuga Lake and other regional waterbodies in the Finger Lakes region is considered to be substantial. State, regional, and local officials and organizations, along with biologists from Cornell University are developing plans to control, manage, and prevent the spread of the invader, as well as outreach efforts to enlist the public's help in preventing the plant's spread.

  • Langeland, K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The Perfect Aquatic Weed". Castanea 61:293-304.
  • Menninger, H. 2011. Hydrilla verticillata in the Cayuga Inlet: A science‐based review to guide management actions. NY Invasive Species Research Institute,
  • Cornell University, Ithaca, NY. 11 pp.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The New York Invasive Species Clearinghouse, Cornell University Cooperative Extension

Supplier: Tracy Barbaro

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Brief

"Red List Category & Criteria: Least Concern ver 3.1 Year Assessed: 2010 Assessor/s: Zhuang, X. Reviewer/s: Juffe Bignoli, D., Bounphanmy, S., Meng, M. & Homsombath, K. Justification: This species is widespread and locally common and is considered as an invasive in many countries. Its global population needs to be studied to monitor trends. However, it is not considered to be in risk of extinction and is therefore listed as Least Concern."
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Brief

Flowering class: Monocot Habit: Herb
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Hydrilla, Hydrilla verticillata, is an aquatic weed not native to Florida but widespread within the state. It is a submerged, rooted (usually) perennial with long, sinewy branching stems that often reach the surface and form dense mats. The stems are covered in small, pointed, often serrate leaves arranged in 4-8 whorls. Leaf midribs are often reddish with one or more sharp spines. Small pale subterranean tubers occur attached to the roots. Small white flowers grow above the water line on stalks (Godfrey and Wooten 1979, Illinois-Indiana Sea Grant College Program undated).H. verticillata exhibits a degree of penotyoic plasticity (variable physical appearance) in response to age, habitat conditions, and water quality (Kay 1992). Branching is generally sparse in submerged portions of the plant, tending to become profuse at the surface (Langeland 1996).
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Distribution

Range Description

Widespread from the temperate and tropical regions of the Eastern Hemisphere. It is considered an noxious plant in the USA and has been introduced in many European countries. This aquatic plant is believed to be native to Africa, south and southeast Asia.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

National Distribution

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

"
Global Distribution

Asia, Europe and Africa

Indian distribution

State - Kerala, District/s: All Districts

"
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

"Range Description: Widespread from the temperate and tropical regions of the Eastern Hemisphere. It is considered an noxious plant in the USA and has been introduced in many European countries. This aquatic plant is believed to be native to Africa, south and southeast Asia. Countries - Native: Afghanistan; Bangladesh; Belarus; Bhutan; Burundi; Cambodia; China (Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Tibet [or Xizang], Yunnan, Zhejiang); Congo, The Democratic Republic of the; Estonia; Hong Kong; India; Indonesia (Jawa, Maluku, Sulawesi, Sumatera); Iran, Islamic Republic of; Ireland; Japan (Nansei-shoto); Kazakhstan; Kenya; Korea, Republic of; Lao People's Democratic Republic; Lithuania; Malaysia (Peninsular Malaysia, Sabah, Sarawak); Myanmar; Nepal; Papua New Guinea; Philippines; Russian Federation (Altay, Amur, Irkutsk, Khabarovsk, Krasnoyarsk, Primorye, West Siberia); Rwanda; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Uganda; United Kingdom; Viet Nam; Zambia Introduced: Austria; Germany; Hungary; Italy; Spain (Canary Is., Spain (mainland)); United States; Present - origin uncertain:Latvia; Poland"
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Distribution and Habitat in the United States

Hydrilla is documented throughout the southern United States from California to Delaware. In the mid-Atlantic, it occurs in much of the Potomac River, in Virginia and Maryland freshwater tributaries of the Chesapeake Bay, in the Delaware portion of the Nanticoke River, most southern Delaware ponds, and in sites in eastern Pennsylvania. It is not salt tolerant.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Origin

Central Africa

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

introduced; Ala., Calif., Conn., Del., D.C., Fla., Ga., La., Md., Md., Miss., S.C., Tenn., Tex., Va.; Mexico; West Indies; Central America; South America (Venezuela); Eurasia; Africa; Australia.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Distribution: Gregarious in ditches, pools, lakes, wet ricefields and slow-running water streams in S.E. Europe, Africa, Asia and Australia from sea level to 6000'; introduced in America and elsewhere.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

South & East Europe, Africa, South & East Asia to Australia.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Physical Description

Morphology

Description and Biology

  • Plant: rooted aquatic plant.
  • Leaves: in whorls of 4-5; about ½ in. long; fine-toothed margins, spine at tip.
  • Flowers, fruits and seeds: tiny, translucent to white flowers produced on the upper branches in late summer and fall; tubers grow from the roots; winter buds (turions) are produced in the leaf axils.
  • Spreads: vegetatively through fragments of stems, stolons, or rhizomes, turions, or tubers which are carried on boat livewells, motors and trailers, bait pails and other items, and by ingestion of tubers and turions by waterfowl.
  • Look-alikes: native common waterweed (Elodea canadensis) with leaves in whorls of 3 and no teeth or spines.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Description

Caulescent, glabrous, profusely branched freshwater herb with 5-50 mm long internodes and fibrous roots at some nodes. Leaves oblong-linear to lanceolate, (8-) 10-40 (-50) mm long, (1-) 2-3 mm wide, green, margin serrate-dentate, apex acute-apiculate; nodal scales 2, axillary, membranous with orange brown cilia on margin. Male spathe 1.25-1.50 mm long, bursting open to liberate male flower, beset with subulate appendages. Male flower: sepals reflexed, 1.5-3 mm long; petals linear-spathulate, equalling the sepals, patent or reflexed, obtuse; stamens with minute filaments. Female spathe c. 5 mm long, reddish-brown striped, bidentate. Ovary oblong, 3.4 mm long, with 1.5-10 cm long slender rostrum. Fruit ± terete. 5-7 mm long. Seeds dark brown, c. 2.5 mm long.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Elevation Range

600-1600 m
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Description

Rhizomes and erect stems with turions; subterranean turions cream-brown, appearing as tubers, surface smooth; turions from erect stems olive-green, covered with short, stiff scales. Leaves 8--15(--20) ´ 1.2--4 mm, margins serrulate. Inflorescences: spathe of 2 connate bracts. Flowers 1 per spathe; staminate pedicels 0.5 mm; pistillate flowers with floral tube 10--50 mm; ovary 1-locular. 2n = 32.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Size

The sinewy branching stems of Hydrilla verticillata regularly reach 2 m length and can attain lengths of more than 7.5 m (Cook and Luond 1982, Langland 1996).Hydrilla is an herbaceous perennial that experiences seasonal winter dieback (Carter et al. 1994).
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Diagnostic Description

Diagnostic

"Caulescent, glabrous, profusely branched freshwater herb with 5-50 mm long internodes and fibrous roots at some nodes. Leaves oblong-linear to lanceolate, green, margin serrate-dentate, apex acute-apiculate; nodal scales 2, axillary, membranous with orange brown cilia on margin. Male spathe 1.25-1.50 mm long, bursting open to liberate male flower, beset with subulate appendages. Male flower: sepals reflexed, 1.5-3 mm long; petals linear-spathulate, equalling the sepals, patent or reflexed, obtuse; stamens with minute filaments. Female spathe c. 5 mm long, reddish-brown striped, bidentate. Ovary oblong, 3.4 mm long, with 1.5-10 cm long slender rostrum. Fruits terete, 5-7 mm long. Seeds dark brown, c. 2.5 mm long."
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Synonym

Serpicula verticillata Linnaeus f., Suppl. Pl., 416. 1782
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Look Alikes

In Florida, Hydrilla may be easily mistaken for a related (confamilial) non-native aquatic weed Egeria densa with which it co-occurs in much of the state. The leaves of E. densa occur in whorls of 3-6 and have very fine serrations that can only be discerned under magnification.Hydrilla can also be confused with a native aquatic plant, Elodea canadensis, although this species only occurs in northernmost Florida.
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
It is locally common in rivers and ponds. This species is hardy and tolerant to heavy metals. Many studies have investigated the ecological role of this species in polluted waters (i.e., Wang et al. 2007, Bao 2008, Huang et al. 2009).

Systems
  • Freshwater
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

General Habitat

"Systems: It is locally common in rivers and ponds. This species is hardy and tolerant to heavy metals. Many studies have investigated the ecological role of this species in polluted waters (i.e., Wang et al. 2007, Bao 2008, Huang et al. 2009). List of Habitats: Freshwater"
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

General Habitat

Stagnant ponds
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Lakes, streams, rivers, bayous; introduced; 0--200m.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Depth range based on 4 specimens in 1 taxon.

Environmental ranges
  Depth range (m): 2 - 2
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Trophic Strategy

Autotrophic (photosynthetic).
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Associations

Freshwater anglers recognize the role of hydrilla beds as fish attractors and regularly fish over beds and at their margins. In particular, dense hydrilla beds are common aggregation sites for chain pickerel (Esox niger), whose ambush style of predation benefits from the presence of vegetative cover. Experimental research has indicated that the presence of dense vegetation in general may result in a shift in foraging strategy in fish species, away from a pursuit predator strategy in favor of ambush predation that takes advantage of vegetative cover (Crowder and Cooper 1982, Savino and Stein 1982).In Florida, Hydrilla verticillata often occurs in mixed beds with another non-native aquatic weed Egeria densa. The two plants are very similar in appearance.Invasion History: The broad native range of Hydrilla verticillata is believed to include parts of Asia and India, Australia, and possibly Africa, and the plant has been subsequently introduced occurs on every continent except Antarctica (Pieterse 1981, Cook and Luond 1982, ISSG).The first introduction of the species in North America was through a Florida west coast aquarium dealer in the early 1950s who shipped live H. verticillata from Sri Lanka (dioecious, exclusively female strain) for the aquarium trade under the common name Indian star-vine (Note that more recent genetic studies, e.g., Madeira et al. 2004, suggest the original material may have come from Bangalore, India.). The plants were deemed unsatisfactory and were disposed of into a canal near Tampa Bay where they survived and thrived (McCann et al. 1996). By 1955, samples from this introduced Tampa population had been transported to Miami for cultivation and pet trade sale. Subsequent undocumented accidental/careless releases no doubt followed, as evidenced by the extensive spread of the Sri Lanka biotype throughout Florida and elsewhere in the southeastern U.S.Introduction of the monoecious (Korean) strain of H. verticillata to the eastern seaboard occurred perhaps two decades after the initial Florida introduction. This hydrilla biotype was first reported from Delaware in 1976, and from the Potomac River around 1980 (Madeira et al. 2000).Considering both biotypes together, Hydrilla is now present throughout the southeast, on the east coast from Florida north to Massachusetts, west into Texas, and in Arizona and California as well (Pieterse 1981, Cook and Luond 1982, Langeland 1996). Potential to Compete With Natives: Hydrilla verticillata is an aggressive invader that has been shown capable of displacing native submersed plant communities (Haller and Sutton 1975, Bowes et al. 1977). Dense beds of hydrilla alter the community structure at multiple levels. Water chemistry is altered, zooplankton populations decline, and fish population and community structures are altered as well (Colle and Shireman 1980, Canfield et al. 1983, Schmitz and Osborne 1984). Possible Economic Consequences of Invasion: Hydrilla has been recognized as one of the most invasive weeds in the world and infestations are capable of choking waterways and public water supplies (Illinois-Indiana Sea Grant undated). It is listed as a Category I invasive exotic plant in Florida, indicating that the species is currently altering native plant communities by displacing native species and changing community structures or ecological functions.Worldwide economic impacts of Hydrilla verticillata include impacts relating to infestation of rice fields, irrigation canals, fishponds and public waterways (Cook and Luond 1982). Oxygen depletion is a potentially serious consequence of decomposition of large amounts of hydrilla plant biomass in infested lakes (Engel 1995).Hydrilla control and management is expensive. The state of Florida spent approximately 14.5 million dollars on H. verticillata control in 1994-1995. The economic cost of lost recreational dollars is also considerable. Recreational activies worth $11 million were lost just in Orange Lake (Marion County) in those years when hydrilla infestations entirely choked the lake. (Langeland 1996).
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Population Biology

Schardt (1994) refers to Hydrilla verticillata as the most abundant aquatic plant in Florida public waters, and hydrilla-infested waterbodies occur in seventy percent of the state's freshwater drainage basins. Schardt (1997) reported hydrilla was present in 43% of Florida's public water bodies in 1994, representing an estimated coverage of 38,500 ha.
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Life History and Behavior

Cyclicity

Flowering and fruiting: Throughout the year
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Flowering/Fruiting

Flowering summer--fall.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Flower/Fruit

Fl. Per.: October-January.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Reproduction

The southern Hydrilla verticillata biotype that occurs in Florida is comprised mostly of dioecious (one sex) female plants. Although extensive flowering may occur, the lack of male plants indicates that sexual reproduction is essentially non-existent. The northern (non-Florida) biotype consists of monoecious individuals (male and female flowers occur on the same plant), and at least some sexual reproduction resulting in the setting of fertile seed occurs in this population (Langland and Smith 1984, Madiera et al. 2000). Where reproduction through flowering does occur, wind-pollination is the means of fertilization (Steward et al. 1984).Reproduction of hydrilla in Florida is predominantly if not exclusively through vegetative means. Vegetative strategies include regrowth from stem fragments and clonal reproduction via runners, rhizomes, and tubers (Pieterse 1981, Hurley 1990). Sutton et al. (1992) indicate that one tuber can give rise to as many as 6,000 new tubers per square meter, and Van and Steward (1990) notes tubers can remain viable longer than 4 years.Vegetative reproduction also occurs via specialized axillary buds called turions which reside on the stems in the water column and are somewhat smaller than tubers (Yeo et al. 1984, Spencer et al. 1994). Turions, which are actually underground tubers, become detached from the parent plants to disperse through water movement to new location where they can grow vegetatively into new plants (Hofstra et al. 1990). In colder climates, turions are important as overwintering organs.
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Growth

Where seed production occurs, seeds are poorly dispersed and usually sink to the sediment with perhaps some water current transport occurring as well. Seed set occurs around September and germination commences the following April-May. Maturation is rapid, and plants are capable of flowering just two months after germination (Steward et al. 1984). Hurley (1990) reports seed germination rates are generally less than 50%. Germination of turions occurs at around 18°C (Hurley 1990, Pieterse 1981).
  • Barko J.W. and R.M. Smart. 1981. Comparative influences of light and temperature on the growth and metabolism of selected submersed freshwater macrophytes. Ecological Monographs 51:219-235.
  • Bowes G., Holaday A.S, Van T.K., and W.T. Haller. 1977. Photosynthetic and photorespiratory carbon metabolism in aquatic plants. Proceedings 4th International Congress of Photosynthesis, Reading (UK):289-298.
  • Carter V., Rybicki N.B., Landwehr J.M. and M. Turtora.1994. Role of weather and water quality in population dynamics of submersed macrophytes in the tidal Potomac River. Estuaries 17:417-426.
  • Canfield D.E. Jr., Langeland K.A., Maceina M.J., Haller W.T., Shireman J.V, and J.R. Jones. 1983. Trophic state classification of lakes with aquatic macrophytes. Canadian Journal of Fisheries and Aquatic Sciences 40:1713-1718.
  • Colle D.E. and J.V. Shireman. 1980. Coefficients of condition for largemouth bass, bluegill, and redear sunfish in hydrilla-infested lakes. Transactions of the American Fiseriesh Society 109:521-531.
  • Cook C.D.K. and R. Luond. 1982. A revision of the genus Hydrilla (Hydrocharitaceae). Aquatic Botany 13:485-504.
  • Crowder L.B. and W.E. Cooper. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63:1802-1813.
  • Engel S. 1995. Eurasian Watermilfoil as a Fishery Management Tool. Fisheries 20:pp. 20-27.
  • Godfrey R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States, the Monocotyledons. University of Georgia, Athens, GA. 933p.
  • Haller W.T., and D.L. Sutton. 1975. Community structure and competition between hydrilla and vallisneria. Hyacinth Control Journal 13:48-50.
  • Haller W.T., D.L. Sutton, and W.C. Barlowe. 1974. Effect of salinity on growth of several aquatic macrophytes. Ecology 55:891-894.
  • Hurley L.M. 1990. Field Guide to the Submerged Aquatic Vegetation of Chesapeake Bay. United States Fish and Wildlife Service, Annapolis, MD. 51p.
  • Illinois-Indiana Sea Grant College Program. Undated. Exotic Aquatics on the Move Hydrilla (Hydrilla verticillata) summary page. Available online.
  • Kay S.H. 1992. Hydrilla: A rapidly spreading aquatic weed in North Carolina. North Carolina Cooperative Extension Service, North Carolina State University, Publication AG-449. 11p.
  • Langeland K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The perfect aquatic weed." Castanea 61: 293-304. Available online.
  • Langeland K.A. and C.B. Smith. 1984. Hydrilla produces viable seed in North Carolina lakes. Aquatics 6:20-21.
  • Les D.H. Mehrhoff L.J., Cleland M.A. and J.D. Gabel. 1997. Hydrilla verticillata (Hydrocharitaceae) in Connecticut. Journal of Aquatic Plant Management 35:10-14.
  • Madeira P., Van T., Steward D., and R. Schnell. 1997. Random amplified polymorphic DNA analysis of the phenetic relationships among world-wide accessions of Hydrilla verticillata. Aquatic Botany 59:217-236.
  • Madeira P.T., Jacono C.C, and T.K. Van. 2000. Monitoring hyrilla using two RAPD procedures and the Nonindigenous Aquatic Species Database. Journal of Aquatic Plant Management 38:33-40.
  • Madeira, P.T., Van T.K., and T.D. Center. 2004. An improved molecular tool for distinguishing monoecious and dioecious hydrilla. Journal of Aquatic Plant Management 42:28-32
  • McCann J.A., Arkin L.N., and J.D. Williams. 1996. Nonindigenous aquatic and selected terrestrial species of Florida. Available online.
  • Pieterse, A. H. (1981) Hydrilla verticillata- a review. Abstracts of Tropical Agriculture 7:9-34.
  • Ramey V. 2001. Hydrilla verticillata In: Non-Native Invasive Aquatic Plants in the United States. Center for Aquatic and Invasive Plants. Available online.
  • Savino J.F and R.A. Stein. 1982. Predator-prey interactions between largemouth bass and bluegills as influenced by simulated, submersed vegetation. Transactions of the American Fisheries Society 111:255:266.
  • Schmitz D.C., and J.A. Osborne. 1984. Zooplankton densities in a Hydrilla infested lake. Hydrobiologia 111:127-132.
  • Schmitz D.C., Nelson B.V., Nall L.E., and J.D. Schardt. 1991. Exotic aquatic plants in Florida: A historical perspective and review of the present aquatic plant regulation program. Proceedings of the Symposium on Exotic Pest Plants, University of Miami, Nov. 2-4, 1988, Miami, FL.Schardt J.D. 1994. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA. 83 p.
  • Schardt J.D. 1997. Florida Aquatic Plant Survey Report. Florida Department of Environmental Protection, Bureau of Aquatic Plant Management, Tallahassee, FL. Report nr 942-CGA 86 p.
  • Spencer D., Anderson L., Ksander G., Klaine S., and F. Bailey. 1994. Vegetative propagule production and allocation of carbon and nitrogen by monoecious Hydrilla verticillata (L.f.) Royle grown at two photoperiods. Aquatic Botany 48:121-132.
  • Steward K.K., Van T.K., Carter V., and A.H. Pieterse. 1984. Hydrilla invades Washington, D.C. and the Potomac. American Journal of Botany 71:162-163.
  • Sutton D.L., Van T.K., and K.M. Portier. 1992. Growth of dioecious and monoecious Hydrilla from single tubers. Journal of Aquatic Plant Management 30:15-20.
  • Twilley R.R. and J.W. Barko. 1990. The growth of submersed macrophytes under experimental salinity and light conditions. Estuaries 13:311-321.
  • Van T.K. and K.K. Steward. 1990. Longevity of monoecious hydrilla propagules. Journal of Aquatic Plant Management 28:74-76.
  • Van T.K., Haller W.T., and G. Bowes. 1976. Comparison of the photosynthetic characteristics of three submersed aquatic plants. Plant Physiology 58:761-768.
  • Yeo, R.R., Falk R.H., and J.R. Thurston. 1984. The morphology of hydrilla (Hydrilla verticillata (L.f.) Royle). Journal of Aquatic Plant Management. 22:1-7.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Smithsonian Marine Station at Fort Pierce

Source: Indian River Lagoon Species Inventory

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Molecular Biology and Genetics

Molecular Biology

Barcode data: Hydrilla verticillata

The following is a representative barcode sequence, the centroid of all available sequences for this species.


Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Statistics of barcoding coverage: Hydrilla verticillata

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 7
Specimens with Barcodes: 7
Species With Barcodes: 1
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2013

Assessor/s
Zhuang, X.

Reviewer/s
Juffe Bignoli, D., Bounphanmy, S., Meng, M. & Homsombath, K.

Contributor/s

Justification
This species is widespread and locally common and is considered as an invasive in many countries. Its global population needs to be studied to monitor trends. However, it is not considered to be in risk of extinction and is therefore listed as Least Concern.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

National NatureServe Conservation Status

United States

Rounded National Status Rank: NNA - Not Applicable

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

NatureServe Conservation Status

Rounded Global Status Rank: GNR - Not Yet Ranked

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

"Red List Category & Criteria: Least Concern ver 3.1 Year Assessed: 2010 Assessor/s: Zhuang, X. Reviewer/s: Juffe Bignoli, D., Bounphanmy, S., Meng, M. & Homsombath, K. Justification: This species is widespread and locally common and is considered as an invasive in many countries. Its global population needs to be studied to monitor trends. However, it is not considered to be in risk of extinction and is therefore listed as Least Concern."
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Population

Population
No population information available although it is a common and widespread species.

Population Trend
Unknown
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Population Trend: No population information available although it is a common and widespread species.
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Threats

Major Threats
No specific widespread threats have been reported.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

"Threat [top]: 5, 5.1, 5.5, 5.7 Major Threat (s): No specific widespread threats have been reported."
Creative Commons Attribution 3.0 (CC BY 3.0)

© India Biodiversity Portal

Source: India Biodiversity Portal

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Management

Conservation Actions

Conservation Actions

No conservation measures are in place. More research may be needed to determine population trends and global population.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Control mechanical harvesting and herbicide spraying are common control methods of controlling Hydrilla. Both are expensive and only moderately effective.

  • Power weed cutters mow underwater weeds below the water surface and gather them onto a conveyor. The harvesting process is expensive, costing over $1,000 per acre. Because of Hydrilla’s rapid growth, mechanical harvesting needs to be performed several times per growing season. Since the mowing and removal process cannot capture every single fragment of Hydrilla stem and leaf, water and wind currents moving away from the harvest area can easily carry these fragments to uninfested areas of a waterbody and result in new populations taking root.
  • Chemicals are easier to apply, but also costly. Herbicide spraying works best in small, enclosed bodies of water, and does not work at all in larger bodies the size of a Finger Lake, or in moving water such as a stream, river or canal. Herbicides can also have unintended impacts on native flora, as well. For those reasons, permits for chemical control of Hydrilla are difficult to obtain in New York.
  • Biological control insects as part of efforts to control Hydrilla have been attempted in Florida with mixed results. Leaf-mining flies from Australia and India and a tuber-feeding weevil from India have been used overseas. The insects released are not native to NY, nor are they currently permitted for release in the State. The use of non-native species to attempt to control another non-native species can be risky if the newly released species out-competes native insects, causing a new invasive species problem. The use of sterile grass carp has been used with some success in small lakes in the southern US but would be impractical in lakes the size of the Finger Lakes.
  • Another method of dealing with Hydrilla infestations is the control of water levels. Temporary control of Hydrilla has been shown to result from large-scale, long-term water drawdowns. However, since new plants can grow from the buried tubers, regrowth can take place when water levels are allowed to return to normal. Drawdowns also can have negative environmental impacts on native plant species and on fish populations.
  • Suction harvesting of Hydrilla growth by divers using very strong vacuum hoses can be used to remove Hydrilla from confined areas. However, as with drawdowns, if the underground tubers are not removed by dredging following the suction harvesting, regrowth can take place from the tubers during the next growing season. Further, any fragments that might escape during vacuum activities can float away to root and start new infestations. The “best”, most effective way to control Hydrilla is the prevention of new Hydrilla infestations.
  • Langeland, K. A. 1996. Hydrilla verticillata (L.F.) Royle (Hydrocharitaceae), "The Perfect Aquatic Weed". Castanea 61:293-304.
  • Menninger, H. 2011. Hydrilla verticillata in the Cayuga Inlet: A science‐based review to guide management actions. NY Invasive Species Research Institute, Cornell University, Ithaca, NY. 11 pp.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The New York Invasive Species Clearinghouse, Cornell University Cooperative Extension

Supplier: Tracy Barbaro

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Prevention and Control

Physical, chemical and biological controls have been used for control of hydrilla, with varying levels of success. Water level drawdowns have generally been ineffective in our area. Mechanical aquatic weed harvesters provide temporary relief and open boating lanes, but resulting plant fragments can help spread the vegetation faster. Contact herbicides provide temporary control, but systemic herbicides provide more long-term control. Herbivorous fish such as sterile grass carp have been used for hydrilla control where allowed by law. Other biological controls are still being investigated. Each control method has its drawbacks and liabilities. On the Potomac River and other parts of the Chesapeake Bay watershed, resource managers struggle with hydrilla because submerged aquatic vegetation, including hydrilla, provides water quality benefits and habitat for fish and shellfish.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Relevance to Humans and Ecosystems

Risks

Ecological Threat in the United States

Hydrilla outcompetes native submerged aquatic vegetation and can quickly fill a pond or lake, thus choking off the water body for boating, fishing, swimming and other recreational uses. Although non-native and invasive, it provides good quality habitat for fish and shellfish as well as water quality benefits.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Wikipedia

Hydrilla

Hydrilla (Esthwaite Waterweed or Hydrilla) is a genus of aquatic plant, usually treated as containing just one species, Hydrilla verticillata, though some botanists divide it into several species. Synonyms include H. asiatica, H. japonica, H. lithuanica, and H. ovalifolica. It is native to the cool and warm waters of the Old World in Asia, Europe, Africa and Australia, with a sparse, scattered distribution; in Europe, it is reported from Ireland, Great Britain, Germany, and the Baltic States, and in Australia from Northern Territory, Queensland, and New South Wales.[1][2][3]

The stems grow up to 1–2 m long. The leaves are arranged in whorls of two to eight around the stem, each leaf 5–20 mm long and 0.7–2 mm broad, with serrations or small spines along the leaf margins; the leaf midrib is often reddish when fresh. It is monoecious (sometimes dioecious), with male and female flowers produced separately on a single plant; the flowers are small, with three sepals and three petals, the petals 3–5 mm long, transparent with red streaks. It reproduces primarily vegetatively by fragmentation and by rhizomes and turions (overwintering), and flowers are rarely seen.[2][4][5][6]

Hydrilla has a high resistance to salinity (>1-100000 ppt) compared to many other freshwater associated aquatic plants.

The name Esthwaite Waterweed comes from its occurrence in Esthwaite Water in northwestern England, the only English site where it is native, but now presumed extinct, having not been seen since 1941.[7] Hydrilla closely resembles some other related aquatic plants, including Egeria and Elodea.

Status as an invasive plant[edit]

Foliage detail

Hydrilla is naturalised and invasive in the United States following release in the 1960s from aquariums into waterways in Florida. It is now established in Canada and the southeast from Connecticut to Texas, and also in California.[8] By the 1990s control and management were costing millions of dollars each year.

Hydrilla can be herbicides and it is also eaten by grass carp, itself an invasive species in North America. Insects used as biological pest control for this plant include weevils of the genus Bagous and the Asian hydrilla leaf-mining fly (Hydrellia pakistanae). Tubers pose a problem as they can lie dormant for a number of years, making it even more difficult to remove from waterways and estuaries.

As an invasive species in Florida, Hydrilla has become the most serious aquatic weed problem for Florida and most of the U.S. Because it was such a threat as an invasive species, restrictions were placed to allow only a single type of chemical, fluridone, to be used as an herbicide. This was done to prevent the evolution of multiple mutants, and resulted in fluridone resistant Hydrilla. “As Hydrilla spread rapidly to lakes across the southern United States in the past, the expansion of resistant biotypes is likely to pose significant environmental challenges in the future.”[9]

In 2011 the inlet of Cayuga Lake, one of the Finger Lakes in New York State, used the chemical herbicide endothall to try to head off a possible future disaster. The first year nearly $100,000 and numerous man-hours were spent trying to eradicate the Hydrilla infestation. Follow-up treatments were planned for at least five years. The City of Ithaca as well as other local officials are willing to pay the price because without quick action the plant could get into the lake and possibly spread to other Finger Lakes in the region.[10]

Phytoremediation[edit]

This abundant source of biomass is a known bioremediation hyperaccumulator of Mercury, Cadmium, Chromium and Lead, and as such can be used in phytoremediation.[11]

References[edit]

  1. ^ Flora Europaea: Hydrilla
  2. ^ a b Flora of Taiwan: Hydrilla
  3. ^ Australian Plant Name Index: Hydrilla
  4. ^ Flora of NW Europe: Hydrilla verticillata
  5. ^ Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. ISBN 0-340-40170-2
  6. ^ Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan ISBN 0-333-47494-5.
  7. ^ Environmental Change Network: Esthwaite Water
  8. ^ Flora of North America: Hydrilla verticillata
  9. ^ Peterson, A. T.; Papes, M.; Kluza, D. A. (2003). "Predicting the potential invasive distributions of four alien plant species in North America". Weed Science 51 (6): 863. doi:10.1614/P2002-081.  edit
  10. ^ 2011 Hydrilla Eradication Efforts – Cornell Cooperative Extension of Tompkins County. Ccetompkins.org (2013-09-16). Retrieved on 2014-05-02.
  11. ^ McCutcheon, Steven C. and Schnoor, Jerald L. (2004). Phytoremediation: Transformation and Control of Contaminants. John Wiley & Sons. p. 898. ISBN 978-0-471-45932-3. 
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

Unreviewed

Article rating from 0 people

Default rating: 2.5 of 5

Notes

Comments

Hydrilla verticillata apparently entered the United States in 1959 at Miami, Florida (D. F.F. Austin 1978). It was introduced as an aquarium plant, star-vine or oxygen plant (D. P. Tarver et al. 1978). By 1960 the species was reported as naturalized in Florida (G. E. Allen 1976). 

 Hydrilla verticillata is widely distributed in the Eastern Hemisphere but it is uncertain as to where it is truly native. It grows in a variety of aquatic habitats ranging from acidic to basic, oligotrophic to eutrophic, fresh to brackish, and from a few centimeters to a meter or more if light penetrates that deeply. Growth and spread often are rapid. Stem fragments become rooted by fine, unbranched adventitious roots and soon produce vegetative reproductive structures from both subterranean and erect stems. Tubers produced on subterranean stems are pale brown; those produced on erect stems are dark olive-green and covered with short, stiff scales. Both types germinate quickly to produce new stems.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Comments

The plant is eaten by some fresh water fish and may be used as manure wherever it occurs in large quantities. It becomes a serious menace to navigation in large lakes and in irrigation canals as it reduces the rate of flow of water.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!