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Non-Native Invasive Aquatic Plants in the United States
Center for Aquatic and Invasive Plants, University of Florida |
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Non-Native Invasive Aquatic Plants in the United States
Center for Aquatic and Invasive Plants, University of Florida |
pronounced: lag ar o si fon mah yor (long/short marks) (audio clip)
from:
"likely refers to the long, thin tubes that allow the female flowers to reach the water
surface"
Habitat:
Quick ID:
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)
How it got here:
Potential to spread elsewhere in 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).
Problems/Effects:
Control:
What you can do
Laws and lists:
Want to know more?
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 Lagarosiphon major that was used to
develop this web page. More research items about this plant may be found at APIRS:
Lagarosiphon major: rooted submersed macrophyte; leafy submersed stems;
stems to 20 ft. long; leaves alternate
on the stems, blades recurved downward; tiny white (female) flowers reach the surface on long,
thin
tubes (pollination occurs on the water surface)
More complete identification:
Lagarosiphon major (Ridley) Moss ex Wager
Original description: Trans. Proc. Roy. Soc. S. Africa 16(2):191-201. 1928.
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
native to
the U.S.; however they are here, whereas Lagarosiphon is not (April, 2001).
--hydrilla leaves have teeth on the margins and a few teeth on the
underside midribs, making hydrilla rough to the touch when pulled through the hands;
Lagarosiphon major leaves have no teeth on the margins or midribs and are not
rough
to the touch
--elodea leaves occur in whorls of 3 around the stem,
Lagarosiphon
major leaves are alternate along the stem
--egeria leaves are in whorls of 4-5 and do not dramatically "recurve";
Lagarosiphon leaves are alternate and greatly recurve
Origin:
Distribution in the U.S.:
There is no information in the scientific literature as to the potential for Lagarosiphon
major to spread in the U.S.
Lagarosiphon major
Lagarosiphon major :
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)
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)
There's plenty you can do to help.
Lagarosiphon major
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.
Anecdotal information about Lagarosiphon major would be appreciated by users
of this web site. Please submit anecdotal information, additional reference citations and
corrections for this page to
CAIP-WEBSITE@ufl.edu