Pacific Island Ecosystems at Risk (PIER)

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Ceratophyllum demersum
L., Ceratophyllaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: jin yu zao

English: common coontail, common hornwort, coontail, hornwort, rigid hornwort

Fijian: lumilumi

Filipino: arigman

French: cératophylle submergé

Japanese: matsumo

Spanish: cama de ranas, cola de zorro

Tagalog: inata

Habit:  aquatic herb

Description:  "A submerged, rootless, densely leafy, perennial, freshwater plant, stems often much-branched, forming large masses, flexuous, the internodes 1 to 3 cm long; leaves in whorls of seven to 10, 1 to 4 cm long, the base gradually or abruptly thickened above the middle, the segments spreading when submerged, collapsing out of water, twice or thrice forked with linear segments; flowers very small, sessile in the leaf axils, each surrounded by minute bracts, a real perianth not present; flower bracts nine to 12, linear, transparent, with numerous short, brown lines; female flowers with a minute ovary and simple style; male flower, anthers white, stamens sessile; fruit black, 4 to 5 mm long, with three spines, the apical spine (style) 11 to 12 mm long, soft, the two basal ones straight to slightly recurved, 9 to 11 mm long, one-seeded.  This submerged plant is distinguished by the presence of one apical and two basal spines on the fruit and its rootless branched stems with forked leaf segments"  (Holm et al., 1977; p. 207).

"Plants entirely submerged; stems brittle or cord-like and flexuous, 0.5-3 m long, branched, forming large masses.  Leaves of seedlings simple, otherwise in whorls of 3-12 per node and dichotomously dissected, variable in length, often 1-2 cm long, ultimate divisions linear.  Style 4-6 mm long.  Achenes ellipsoid, compressed, 4-6 mm long, wingless, with 2 basal spines 2-5 mm long" (Wagner et al., 1999; p. 533).

Habitat/ecology:  "The plant is an inhabitant of shallow ponds, tanks, lakes and stagnant water.  It tends to seek sheltered sites in standing or slowly flowing water where bottoms are much silted.  There are some records of growth in 10 m of water" (Holm et al., 1977; p. 207).

In Hawai‘i, "naturalized in ponds and reservoirs" (Wagner et al., 1999; p. 533). In Fiji, "found near sea level in swamps and ponds and also at the edges of fast-flowing streams and rivers, sometimes associated with Potamogeton crispus (Smith, 1981; p. 148).

Propagation:  Seed, spread by water and birds (Staples et al., 2000; p.65). "Birds are known to fly with pieces of the plant for short distances.  Strong winds, strong currents, foraging animals, or any violent disturbance of the water may tear the plants into many pieces, each of which is a viable source of a new plant"  (Holm et al., 1977; p. 210).  Often used as an aquarium plant (Smith, 1981; p. 148).

Native range:  Cosmopolitan (Wagner et al., 1999; p. 533). "In the Pacific, distribution of the species is spotty; its occurrence in Hawaii is thought to be due to the escape of cultivated plants (Smith, 1981; p. 148).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Fiji
Fiji Islands
Viti Levu Island probably native
Smith, Albert C. (1981) (p. 148)
Vouchers cited: DA 3471, DA 16611, DA 16621, DA 16611, DA 16624, Seemann 386
Guam
Guam Island
Guam Island native
Stone, Benjamin C. (1970) (p. 276)
Voucher cited: Stone 4974 (GUAM), Stone 5019 (GUAM)
Guam
Guam Island
Guam Island native
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 76)
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 533)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 533)
East Maui
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Oppenheimer, Hank L./Bartlett, Randal T. (2002) (p. 5)
West Maui. Voucher cited: Oppenheimer H109906 (BISH)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
Staples, George W./Imada, Clyde T./Herbst, Derral R. (2002) (p. 7)
Voucher cited: E. Funk s.n. (BISH 666283)
Japan (offshore islands)
Ogasawara (Bonin) Islands
Bonin (Ogasawara) Islands   Kato, Hidetoshi (2007)
New Guinea (Indonesia and Papua New Guinea)
New Guinea Island
New Guinea Island native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Papua New Guinea
Bismarck Archipelago
Bismarck Archipelago   Peekel, P. G. [translated by E. E. Henty] (1984) (p. 177)
In ponds, pools and slow-flowing creeks.
Papua New Guinea
Bougainville Islands
Bougainville Island   Foreman, D. B. (1971) (p. 36)
Philippines
Philippine Islands
Philippine Islands native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines
Philippine Islands
Philippine Islands   Merrill, Elmer D. (1923) (p. 141)
In shallow lakes and slow streams.
Solomon Islands
Solomon Islands
Solomon Islands native
Hancock, I. R./Henderson, C. P. (1988) (p. 56)
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Australia (continental) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Australia, Victoria, Western Australia
Australia
Australia (continental)
New South Wales native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Australia
Australia (continental)
Northern Territory native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Australia
Australia (continental)
Queensland native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Canada (British Colombia)
Province of British Columbia
Canada (British Columbia) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Chile (continental)
Chile
Chile (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
China (People's Republic of) native
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
"Streams, ponds, lakes".
China
China
Hong Kong native
Wu, Te-lin (2001) (p. 51)
Colombia
Colombia
Colombia (Republic of)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 78)
Costa Rica
Costa Rica
Costa Rica (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Honduras
Honduras
Honduras (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Indonesia
Indonesia
Indonesia (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan
Japan
Japan (country) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Korea
South Korea
South Korea (Republic of)   Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 209)
Malaysia
Malaysia
Malaysia (country of)   Waterhouse, D. F. (1993) (p. 64)
Mexico
Mexico
Mexico (United Mexican States)   Hafliger, Toni J./Wolf, Matthias (1988) (p. 45)
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 515)
"Drains, lakes, lagoons, slow-moving rivers".
Nicaragua
Nicaragua
Nicaragua (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Panama
Panama
Panama (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan
Taiwan Island
Taiwan Island native
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
"Streams, ponds, lakes".
Thailand
Thailand
Thailand (Kingdom of)   Waterhouse, D. F. (1993) (p. 64)
United States (west coast)
United States (west coast states)
USA (California) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam
Vietnam
Vietnam (Socialist Republic of)   Waterhouse, D. F. (1993) (p. 64)
Also reported from
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Canada (except British Colombia)
Canada
Canada (country) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast)
United States (other states)
United States (other states) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast)
United States (other states)
USA (Florida) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

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This page was created on 12 MAY 2005 and was last updated on 13 JAN 2008.