LAGAROSIPHON MAJOR (Roxb.) (Ridley) Moss
African elodea, oxygen weed
Hyrocharitaceae/frog's bit Family
pronounced: lag ar o si fon mah yor
from: lagaros (G.): narrow, thin
siphon (G.): tube
poly (G.): many
major (L.): larger
"likely refers to the long, thin tubes that allow the female flowers to reach the water surface"
Elodea crispa (by those who keep aquaria (Mason 1960)
Happily, Lagarosiphon major does not yet occur in
the wild in the United States, as 2008, so far as is
known. However, experts
have reason to believe that should this plant be introduced to the U.S., the resulting problems
could be as consequential as those caused by another plant in the Hydrocharitaceae family,
- erbaceous perennial
- strictly aquatic, "obligate" (requiring a wet habitat)
- in freshwaters, entirely submersed, spreading at surface
- reproduces from vegetative fragments
- only female plants are known outside its native range (Cook 1987)
- growing from bottom to surface in water to 18 feet (6.6 m) deep (Coffey 1988)
- forming dense stands of stems in the water
- biomass weight to 424 g m2 dryweight (225 tons of wet biomass per acre) in Lake Taupo, New Zealand
- can form a light-blocking canopy so dense and thick (3 feet thick) that Lagarosiphon major easily outcompetes even tall non-canopy forming native species (Rattray, Howard-Williams & Brown 1994)
- 1% light level occurs in as little as .5 m of Lagarosiphon biomass
- because this plant produces roots faster, grows faster both in length and biomass than one of New Zealands native milfoils, Lagarosiphon major "has an early competitive advantage which may explain the dominance this species now has in the littoral zones of many New Zealand lakes" (Rattray, Howard-Williams & Brown 1994)
- "Lagarosiphon major successfully out-competed native species wherever it has colonised New Zealand lakes in the depth zone 2-6 m--normally occupied by native milfoils (Myriophyllum spp.) and pondweeds (Potamogeton spp.)." (Rattray, Howard-Williams & Brown 1994)
- will grow in lakes, rivers, streams and ponds, oligotrophic to eutrophic
- in its original southern Africa range, it grows in high mountain streams and ponds (Wager 1927)
- it prefers cooler waters; temperature tolerances: this plant is winter hardy; optimum temperature, 20-23o
C (68-74oF); maximum temperature, 25o C (77o F) (Kasselmann 1995)
- the determinant of its maximum depth (about 7 m) is pressure (in non-light-limited environments) (Coffey 1988)
- prefers high light intensity; best growth to 600 micro-einsteins/m2/h (Schwarz and Howard-Williams 1993)
- it is an efficient photosynthesizer and has a low light compensation point, facts which promote its weediness
- "it may be significant that the three known colonies in Dalmuir (England) are also below a point where warm water is discharged" (Silverside and Raymond 1976)
- in one study, even though the nutrient conditions in one lake were higher than in the second lake, this plant grew twice as much biomass in the second lake, apparently because of the much higher carbon dioxide concentrations (dissolved inorganic carbon, DIC) in the water of the second lake (Rattray, Howard-Williams & Brown 1991)
- "the competitive success of L. major may be a consequence of greater tolerance to pH stress" than Elodea species (James, Eaton & Hardwick 1998)
- this plant "is not well adapted for growth in ponds that are green with planktonic algae"(McNabb & Tierney 1972)
Lagarosiphon major (Ridley) Moss ex Wager
Original description: Trans. Proc. Roy. Soc. S. Africa 16(2):191-201. 1928.
- rooted in the hydro-soil by numerous thread-like unbranched roots
- stems submersed; brittle; 3 mm (1/8 in.) in diameter; growing to 20 feet long; branching every 10-to-12 nodes; reaching the surface to spread into thick mats
- leaves submersed; greatly recurved; stiff; alternate spirally along
the stem; leaves linear to linear-lanceolate; to 16 mm (1 in.) long by 2 mm (1/16 to 1/8 in.) wide;
leaves 3-veined with visible midvein; leaf margins minutely toothed; at stem tips, leaves are very
- flowers tiny, transparent to white or pinkish; all parts in 3's; in its native
range, female flowers reach the surface on long thread-like tubes (to 10 in.
long); on the surface they bump into and are pollinated by free-floating male flowers (Cook
1987); male flowers form in the leaf axils, after which they rise to the surface
where they sail about; staminate spathes enclose many flower buds, carpellate spathes enclose
only one flower
- fruit capsule is beaked; seeds 1/8 in. long, averaging
nine to a fruit
- outside its native range, only female plants are known and thus
reproduction is only by vegetative
As a submersed, long-stemmed plant having many small narrow leaves,
Lagarosiphon major might be confused with three other plants in the
U.S. As chance would have it, two of these three other plants are themselves also not
the U.S.; however they are here, whereas Lagarosiphon is not (early 2008).
It is believed that this plant was in New Zealand for some time before it was recognized as a
plant distinct from Elodea canadensis in the 1950s. By the time it was recognized,
Lagarosiphon major was already a major weed there. (Healy)
Here is a comparison of all four of these look-alike plants.
- non- native hydrilla (Hydrilla verticillata ):
native elodea (Elodea canadensis)
native lake hygrophila (Hygrophila costata (H. lacustris)): non-native egeria (Egeria densa)
--egeria leaves are in whorls of 4-5 and do not dramatically "recurve"; Lagarosiphon leaves are alternate and greatly recurve
- Lagarosiphon major is native in southern Africa
- there are about 15 other species of Lagarosiphon native in
southern Africa, Madagascar and India
Distribution in the U.S.:
- Lagarosiphon major does not yet occur in the wild in the United States (early 2008).
The best way to track the spread of invasive aquatic plants may be to identify
the drainage basins (watersheds) they have been discovered in. Drainage maps give useful
information to eco-managers because drainage maps show precisely where the plants are, making
it easier for managers to infer where the plants might go next, and thus where to take preventive
How it got here:
Potential to spread elsewhere in U.S.:
There is no information in the scientific literature as to the potential for Lagarosiphon
major to spread in the U.S.
- One case study from New Zealand suggests that once a submersed weed is introduced, its further
distribution is significantly associated with boating and fishing activities (Johnstone, Coffey &
Howard Williams 1985).
- Lagarosiphon major is fast-growing
- may totally fill the volume of a large shallow lake (to 3 m deep)
- fills water control channels
- in New Zealand, Lagarosiphon major is a major aquatic weed problem recorded in many lakes
- in England, this plant was reported in 1976 as being "well established in scattered localities
in the south, now, two decades later, Lagarosiphon major is "actively displacing"
Elodea species in "some lentic British waters" (James, Eaton & Hardwick 1998); it
was first recorded in England in 1944 (Silverside and Raymond 1976)
- "within two years of the first record of L. major in the boat harbour it had
largely replaced E. canadensis there" (Coffey 1975)
- within 13 years from its first record on the lake, the plant occupied almost all of the 161 km
length of the littoral zone (Howard-Williams 1988)
- in New Zealand lakes, this plant has attained biomass weights of 165-424 g m2
dryweight; if this plant, like hydrilla, is 99% water, then the weight of the plant as an infestation
in the water is in the range of 16500-42400 g m2 (which converts to 88-225 tons
of plant biomass per acre)
- heavy booms protecting hydro-electric power plants' water intake units "fail when a massive
amount of weed is liberated after storms" (Chapman 1974)
- with its canopy spreading across the top part of the water, it is able to shade out and thus
outcompete other submersed species; 1% light level occurs through as
little as .5 m of Lagarosiphon biomass (Schwarz and Howard-Williams 1993) (only
1% of the sunlight can pass through as little as 1.5 ft of a Lagarosiphon infestation)
- in spite of one of its common names, oxygen weed, in a dense infestation of
Lagarosiphon major there often is less oxygen present than in the surrounding water:
thus dense infestations, "in such quantities confer no oxygen benefit on fish and other animals in
the lake" (Chapman 1974)
- Lagarosiphon major caused a power outage in 1968 when it blocked the intake
screens at Aratiatia hydro station in New Zealand
- the plant is detrimental to recreation in Hamilton Lake and Lake Rotorua, New Zealand
the action of mechanical harvestors and chopping machines causes
fragmentation, which helps spread Lagarosiphon major; "if the weed is cut in
mid-summer, the infestation (1m or 6 m) is completely restored by the fall" (Chapman 1974)
the herbivorous (plant-eating) biological control fish, the Chinese grass
carp, has a moderate feeding preference for Lagarosiphon major (Edwards 1975;
Chapman & Coffey 1971)
strong>the aquatic herbicide fluridone was deemed ineffective when used against
Lagarosiphon major in a New Zealand lake (Wells & Coffey 1984); as for another
aquatic herbicide, diquat, "only minimal
herbicidal effects" were noted and so several formulations of diquat were deemed ineffective
against the plant in New Zealand streams (Tanner & Clayton 1984) and diquat "is not effective in
turbid water" (Clayton 1998); on the other hand, diquat
applications are believed to have affected this plant's growth in Lake Rotoroa (Tanner & Clayton
1990); sodium arsenite herbicide effects on this plant were described as "spectacular" in 1960,
but 24 years later, high arsenic levels persisted in soil and plants (Tanner & Clayton 1990), and
"little of the original arsenic applied for weed control was lost from the lake between 1959 and 1992"
(Clayton & Tanner 1994)
What can you do?
First, clean your boat before you leave the ramp! Transporting
plant fragments on boats, trailers, and in livewells is the main introduction route to new lakes and
But, there's plenty more you can do to help.
Laws and lists:
- is "state-listed" by Florida and North Carolina
- is on the Florida Prohibited Plants list, Florida Department of
- is a "Class A Noxious Weed", North Carolina Department of Agriculture
- is on the Federal List of Noxious Weeds (USDA/APHIS, 2000)
Want to know more?
The information contained on this wep page was extracted from
published scientific literature and agency reports. It is important to know that plant research, like most
areas of scientific research, is still relatively young and incomplete--much may have been
published about the physiology of one plant but not about its management; much may have been
published about how to culture and grow another plant but not about its natural ecology.
Thousands of research articles may have been published about one invasive plant, but perhaps
only a dozen about another.
If you want to read the research yourself, perhaps to clarify or expand an area of information
contained here, or to help determine your own line of research, you are welcome to query the
world's largest collection of international scientific literature about aquatic, wetland and invasive
plants, the APIRS
bibliographic database, which contains more than 54,000 citations and their content
keywords. Or you might want to ask us to do
it for you and mail or e-mail the search results to you.
This is the literature about Hygrophila polysperma that was used to
develop this web page. More research items about this plant may be found at APIRS:
- Chapman VJ, Coffey BJ. 1971. Experiments with grass carp in controlling
exotic macrophytes in New Zealand. Hydrobiologia 313-323
- Chapman VJ, JMA Brown, FI Dromoogle and BT Coffey. 1971.
vegetation of the Rotorua and Waitkato Lakes. NZ J. Marine and Freshwater Res. 5(2): 259-79
- Chapman VJ, JMA Brown, CF Hill and JL Carr. 1974. Biology of
excessive weed growth in the hydro-electric lakes of the Waikato River, New Zealand.
- Clayton JS, Tanner CC. 1982. An alternative formulation of diquat for
control of submerged aquatic weeds. Proc. 35th N.Z. Weed and pest Control Conf. pp. 261-264
- Clayton JS, Tanner CC. 1994.. Environmental persistence and fate of
applied for aquatic weed control. IN: Arsenic in the Environment, Part I: Cycling and
Characterization. JO Nriagu, ED, pp. 345-363
- Clayton JS, Chapman VJ, Brown JMA. 1980. Submerged vegetation of
Rotorua and Waikato Lakes. New Zealand J. Marine and Freshwater Res. 15:(44):447-487
- Coffey BT, Wah CK. 1988. Pressure inhibition of anchorage-root
in Lagarosiphon major (Ridl.) Moss: a possible determinant of its depth range.
Aquatic Botany 29:289-301
- Cook CDK. 1982. Pollination mechanisms in the Hydrocharitaceae.
In: "Studies on Aquatic Vascular Plants", J-J Symoens, SS Hooper and P Compere,
eds, pp. 1-15, Royal Bot. Society of Belgium, Brussels
- Cook CDK. 1990. Aquatic Plant Book. SPB Academdic Publishing.
- Eady F. 1974. The aquatic weed control problem 2. Methods of control.
N.Z. J. Agri. Sept:50-53
- Edwards DJ. 1975. Taking a bite at the waterweed problem. New
Zealand J. Agr. 130(1):33, 35-36
- Haynes RR. 1988. Reproductive biology of selected aquatic plants.
Annals of the Missouri Botanical Garden 75(3):805-810
- Howard-Williams C, Davies J. 1988. The invasion of Lake Taupo by the
submerged water weed Lagarosiphon major and its impact on the native flora.
New Zealand J. Ecol. 11:13-19
- Johnstone IM, Coffey BT, Howard-Williams C. 1985. The role of
recreational boat traffic in interlake dispersal of macrophytes: A New Zealand Case Study. J.
Environ. Management. 20:263-279
- Lancaster RJ, Coup MR, Hughes JW. 1971. Toxicity of arsenic present
in lakeweed. N.Z. Veterinary Journal 19(7):141-5
- Mason R. 1960. Three waterweeds of the family Hydrocharitaceae in
New Zealand. New Zealand J. Science 3(3):382-395
- Mason R. 1965. Selected water plants of the Waitko. Dept. Scientific
and Indust. Research, Botany Div.
- Matthews LJ. 1960. Aquatic weed control. Proc. New Zealand Weed
Control Conf. , 13:58- 61
- McNabb C. Jr, Tierney D.P. 1972. Growth and mineral accumulation of
submersed vascular hydrophytes in pleioeutrophic environs. Techn. Rept. NO. 26, Inst. Water
Res., Michigan State Univ. , East Lansing, Michigan, 33 pp.
- Montiero A, Vasconcelos T. 1998. Management and ecology of aquatic
plants. Proc. 10th EWRS Intern'l Symp. on Aquatic Weeds, European Weed Research Soc. ,
21-25. September 1998, 444 pp.
- Rattray MR, Howard-Williams C, Brown, JMA. 1994. Rates of early
growth of propagules of Lagarosiphon major and Myriophyllum
triphyllum in lakes of differing trophic status. New Zealand J. Marine Freshwtaer Res.
- Rattray MR, Howard-Williams C, Brown, JMA. 1991. The
photosynthetic and growth rate responses of two freshwater angiosperms in lakes of different
trophic status: Responses to light and dissolved inorganic carbon. Freshwter Biol. 25:399-407.
- Samways MJ, Stewart DAB. An aquatic ecotone and its significance in
conservation. Biodiversity and Conservation 6(10): 1429-1444
- Schwarz AM, Howard-Willimas, C. 1993. Aquatic weed-bed structure
and photosyntesis in two New Zealand lakes. Aquatic Bot. 46: 263-281
- Silverside AJ, Raymond CJ. 1976. Lagarosiphon major.
Glasg. Nat. 19(4):343
- Tanner CC, Clayton JS. 1984. Control of submerged weeds in flowing
water using viscous gel diquat. Proc. 37th N.Z. Weed and Pest Control Conf. , NZWPC Soc. ,
Palmer, pp. 46-49
- Tanner CC, Clayton JS. 1990. Persistence of arsenic 24 years after
sodium arsenite herbicide application to Lake Rotoroa, Hamilton, New Zealand. New Zealand J.
Marine Freshwater Research 24:173-179
- Tanner CC, Clayton JS, Coffey BT. 1990. Submerged-vegetation
changes in Lake Rotoroa (Hamilton, New Zealand) related to herbicide treatment and invasion
by Egeria densa. New Zeland J. of Marine and Freshwter Research 24(1):45-58
- Wells RDS, Coffey BT. 1984. Fluridone- Late Rotoiti efficacy trial.
Proc. 37th N.Z. Weed and Pest Control Conf., pp. 42-45
- Wells RDS, Dewinton MD, and Clayton JS. 1997. Successive
macrophyte invasions within the submerged flora of Lake Tarawera, Central North Island, New
Zealand. New Zealand J. Marine and Freshwater Research 31(4):449-459
Other web sites that treat Lagarosiphon major:
This web page was authored in June, 2001, by Victor Ramey (Center for Aquatic and Invasive Plants, University of Florida), with significant contribution from Barbara Peichel (Sea Grant, University of Minnesota). The information contained herein is based on the literature found in the APIRS database.|