Pacific Island Ecosystems at Risk (PIER)

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Vallisneria americana
Michx., Hydrocharitaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Vallisneria gigantea Graebn.

Common name(s): [more details]

English: American eelgrass, eel grass, flumine Mississippi, tape grass, water celery, wild celery

Habit:  aquatic herb

Description:  "Submerged aquatic perennial.  Several ribbon-like leaves of varying lengths borne on short vertical stems, the latter arising as short-stemmed clusters from nodes of horizontal rhizomes.  Numerous, fibrous, unbranched roots borne about the bases of the vertical shoots.  Longer leaves commonly with their tips more or less floating on the water surface.  Leaves with scarcely perceptible midrib, to transmitted light appearing very fine lined and with irregular darker green partial cross lines.  Leaf margins bearing minute staggered teeth.  Plants dioecious.  Male inflorescence short stalked in a closed spathe within which some 200 tightly packed slender-pedicillate staminate flowers are borne.  Staminate flowers tiny, with 3 very thin, completely transparent, spoonlike sepals, 2 of equal size, the third, somewhat smaller.  Above and opposite the smaller sepal is the smaller, tongue-like, completely transparent petal.  Above and between the 2 larger sepals is a single, transparent, much reduced sterile stamen.  Fertile stamens 2, filaments fused at the base.  Pistillate flowers borne singly from the leaf axils, each at the end of a peduncle as long as or longer than the longest leaves.  Bud enclosed in a transparent spathaceous envelope which tightly invests it.  As the flower becomes fully developed the spathe splits at the summit and by elongation of the floral tube the flower extends beyond the spathe, the latter ultimately appearing like a bract at the base of the very much elongated fruit.  At anthesis, the open summit of the female flower is at the water surface.  Subsequent to pollination (and presumably fertilization), the flower stalk coils markedly, thus pulling the developing fruit well beneath the surface of the water where it matures.  Floral tube long-cylindrical, surmounted by three spreading, ovate-oblong, thickish persistent sepals about 3-4 mm long.  Alternate with each sepal, just above the sinus between two sepals, is a tiny rudimentary petal which soon disintegrates.  Style short, stigmas 3, each cleft to the base.  Fruit 1-locular, bearing 250-500 seeds, or thereabouts, throughout its length.  Mature capsule dehisces longitudinally by one valve and the seeds are shed in a copious mass of gelatinous material"  (Godfry & Wooten, 1979; p. 74).

"Scapes: staminate scapes 30-50 mm, submersed; pistillate scapes elongate, projecting flowers to surface. Leaves 10-110, 0.3-1.5 cm; leaf blade 3-zoned longitudinally, margins entire to serrate. Flowers: staminate flowers 1-1.5 mm wide; stamens 2, filaments basally connate; pistillate flowers solitary, rarely in umbel-like clusters"  (Flora of North America online).

"Leaf blades 6 inches to 6 feet x 0.25-1.2 inches, margins entire to finely toothed, staminate flowers numerous per spathe, ca. 0.05 inches in diameter, stamens upright, filaments partly or wholly united; pistillate flowers solitary (rarely in umbels), sepals 0.1-0.25 inches long, sterile stamens conspicuous, ±fused to style bases, stigmas not fringed"  (Staples & Herbst, 2005; p. 667).

Habitat/ecology:  "In both quiet and swiftly flowing waters"  (Godfry & Wooten, 1979; p. 74).

Propagation:  Seed

Native range:  North America, West Indies; Central America; Asia (Flora of North America online).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Staples, George W./Imada, Clyde T./Herbst, Derral R. (2003) (p. 13)
Vouchers cited: T. Flynn 897 (BISH), T. Flynn 6196 (BISH)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Oppenheimer, Hank (2008) (p. 29)
West Maui. Voucher cited: Oppenheimer & C. Brosius H120514 (BISH, PTBG)
State of Hawaii
Hawaiian Islands
O‘ahu Island   Bishop Museum (U.S.A. Hawaii. Honolulu.) (1984) (voucher ID: BISH 471826)
Taxon name on voucher: Vallisneria americana Michx.
Papua New Guinea
Papua New Guinea (eastern New Guinea Island)
Papua New Guinea (eastern New Guinea Island) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines
Philippine Islands
Philippine Islands native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines
Philippine Islands
Philippine Islands native
Merrill, Elmer D. (1925) (p. 26)
As Vallisneria gigantea Graebn. In lakes and slow streams at low altitudes.
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Cambodia
Cambodia
Cambodia (Kingdom of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Canada (British Colombia)
Province of British Columbia
Canada (British Columbia) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
China
China
China (People's Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Guatemala
Guatemala
Guatemala (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)
Japan
Japan
Japan (country) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
North Korea
North Korea
North Korea (Democratic People's Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Korea
South Korea
South Korea (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico
Mexico
Mexico (United Mexican States) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (Oregon) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (California) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (Washington) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
Vietnam
Vietnam
Vietnam (Socialist Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
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., Nat. Res. Cons. Serv. (2013)
United States (continental except west coast)
United States (other states)
United States (other states) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (continental except west coast)
United States (other states)
USA (Florida) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Comments:  "Two distinct phenotypes are represented among Hawaiian plants: a diminutive plant with leaves only 15-40 cm long and 6-10 mm wide; and a robust plant with leaves exceeding 1 m in length and 3 cm wide.  Both phenotypes are sold as aquatic ornamentals; the latter is also eaten as a potherb and is sold for that purpose in local produce markets" (Staples, Imada & Herbst, 2003; p. 13).

Additional information:
Additional online information about Vallisneria americana is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Vallisneria americana as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Vallisneria americana may be available from the Germplasm Resources Information Network (GRIN).

References:

Bishop Museum (U.S.A. Hawaii. Honolulu.). 1984. Voucher specimen #BISH471826(Flynn, T. 897).

Flora of North America Editorial Committee, eds. 2013. Flora of North America North of Mexico (online edition).

Godfrey, Robert K./Wooten, Jean W. 1979. Aquatic and wetland plants of southeastern United States: Monocotyledons. University of Georgia Press, Athens. 712 pp. ISBN 0-8203-0420-4.

Merrill, Elmer D. 1925. An enumeration of Philippine flowering plants, vol. 1 [reprint]. Bureau of Printing, Manila. 463 pp.

Oppenheimer, Hank. 2008. New Hawaiian plant records for 2007. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2007. Bishop Museum Occasional Papers 100:22-38.

Staples, George W./Imada, Clyde T./Herbst, Derral R. 2003. New Hawaiian plant records for 2001. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2001-2002. Part 2: Notes. Bishop Museum Occasional Papers. 74:7-21.

U. S. Government. 2013. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2013. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2013. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.


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

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This page was created on 12 FEB 2010 and was last updated on 6 JUL 2010.