L., Hydrocharitaceae
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L., Hydrocharitaceae |
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Present on Pacific Islands? no
Primarily a threat at high elevations? no
Common name(s): [more details]
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Chinese: da ci zao |
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English: bushy pondweed, holly-leaf naiad, holly-leaf waternymph, holly-leaved waternymph, marine naiad, marine naiad, spiny-leaf naiad, spiny naiad, spiny waternymph, water nymph |
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French: naide marine |
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Japanese: ibaramo |
Habit: aquatic herb
Description: "An herbaceous, dioecious, bright to pale green, submerged, rooted, quite variable aquatic plant growing to 80 cm, may be extremely brittle, adventitious roots from base and lower nodes; stems stout, dichotomously branched, spreading or ascending, may be glabrous sparsely toothed; leaves flat, almost always fleshy and sometimes triangular in cross-section, 0.5 to 4.5 cm long, 1.5 to 3.5 cm wide, tip acute to blunt, serrate with 5 to 10, rarely 40 marginal spines or teeth each side; spines may be greater than, equal to, or less than leaf width; dorsal leaf surface mostly with 1 to several spines; sheath with or without 1 to 5, rarely 10, mostly inconspicuous spines; auricles absent, or about 0.02 mm long if present; flowers solitary; staminate flower enclosed in spathe, spathe apex with or without a few minute spines, anthers 4-celled, 2.5 to 3.5 mm wide; pistillate flowers, 2 to 4 stigmas, 0.9 to 2 mm, spathe absent; fruit 1-seeded, plump, often reddish, finely reticulate, slightly asymmetrical, may have scurphy surface; seed elliptic to ovate, narrowing toward the tip, somewhat compressed, about 4 mm long and 2.5 mm wide, with rather irregularly arranged isodiametrical shiny testa patterns" (Holm et al., 1997; p. 497).
Description from Flora of North America
Habitat/ecology: Forms dense mats that choke out other species. "The weed inhabits saline, alkaline and fresh waters of ponds, lakes, reservoirs, and slow-moving streams and canals. Few species of aquatic weeds are aggressive in colonizing brackish waters (between fresh and salt water) but N. marina is conspicuous in doing so" (Holm et al., 1997; p. 497).
Propagation: Seeds and rooting of fragments (Holm et al., 1997; p. 499).
Native range: Nearly cosmopolitan in fresh or brackish wetlands (GRIN).
Presence:
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Country/Terr./St. & Island group |
Location |
Cited status &
Cited as invasive & Cited as cultivated & Cited as aboriginal introduction? |
Reference &
Comments |
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French Polynesia
Clipperton Island |
Clipperton (Arue, Avera) Island |
Sachet, M.-H. (1962) (p. 92)
Var. latifolia A. Br. |
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State of Hawaii
Hawaiian Islands |
O‘ahu Island |
introduced
invasive |
Shannon, Robynn K./Wagner, Warren L. (1996) (p. 14)
Voucher cited: Limu woman 269 (US) Probably extirpated. |
Control: Information on control from the Mississippi State University Extension Service.
Additional information:
Information and photos at the University of California Statewide Integrated Pest Management Project
Additional online information about Najas marina is available from the Hawaiian Ecosystems at Risk project (HEAR).
Information about Najas marina as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).
Taxonomic information about Najas marina may be available from the Germplasm Resources Information Network (GRIN).
References:
Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James. 1997. World weeds: natural histories and distribution. John Wiley & Sons. 1129 pp.
Sachet, M.-H. 1962. Geography and land ecology of Clipperton Island. Atoll Research Bulletin No. 86. Pacific Science Board, National Academy of Sciences, Washington. 115 pp.
Shannon, Robynn K./Wagner, Warren L. 1996. New records of Hawaiian flowering plants primarily from the United States National Herbarium. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1995. Part 2: Notes. Bishop Museum Occasional Papers. 46:13-15.
Staples, George W./Herbst, Derral/Imada, Clyde T. 2000. Survey of invasive or potentially invasive cultivated plants in Hawai‘i. Bishop Museum Occasional Papers No. 65. 35 pp.
U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).
U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).