Paspalum vaginatum Sw., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 7 (Go to the risk assessment)

Other Latin names:  Palspalum distichum sensu auct. non L.

Common name(s): [more details]

English: biscuit grass, knot grass, knottweed, salt grass, saltwater couch, saltwater paspalum, seashore grass, seashore paspalum, silt grass, swamp couch

Fijian: kambutu

French: herbe rampante

Maori (Cook Islands): mauku ta‘atai, mauku ta‘atai, mauku vairākau

Marquesan: matie, mutie

Marshallese: katejukjuk, wûjooj

Niuean: mosie kalalahi

Samoan: mutia

Spanish: grama de costa, grama de mar, gramilla, gramilla blanca, gramón

Habit:  grass

Description:  "Extensively creeping perennials, stoloniferous, often forming extensive colonies, the stolons slender and wiry to stout and slightly fleshy; culms slightly compressed, 2.5-5 (-10) dm long, glabrous, the flowering ones usually shorter, usually grooved, ± branching, sterile culms with short, broad, loose, often overlapping sheaths, and conspicuously distichous, stiffly ascending blades, or bladeless.  Sheaths often keeled, with small auricles; ligule membranous, ca. 0.5 mm long, with a ring of soft white hairs behind it, the hairs sometimes up to 5 mm long; blades usually stiff, ascending at an uniform angle, 2.5-15 cm long, 3-8 mm wide at base, narrower than summit of sheath, apex attenuate, involute, base abruptly contracted.  Racemes 2 (-5), opposite or closely approximate, at first erect and appressed together, usually spreading or reflexed at maturity, often subfalcate, 1.5-7.5 cm long, rachis naked at base, 1-2 (-2.5) mm wide, triangular, flexuous, margins minutely scabrous; spikelets pale, solitary, imbricate, oblong, 3-4.5 mm long, 1.2-1.5 mm wide; first glume rarely developed, second glume and first lemma equal, thin, 3-7-nerved, the midnerve of both usually obscure, glabrous; first lemma usually transversely undulate, sometimes conspicuously so; second lemma convex, usually 3-5-nerved, apex with a few short, stiff cilia, otherwise glabrous; palea flat, 0-2-nerved, similar to lemma.  Caryopsis narrowly obovate, slightly concavo-convex, 2.5-3 mm long, subacute"  (Wagner et al., 1999; pp. 1577-1578).

Description from GrassBase.

See also Paspalum distichum L. for records of this closely related species.  Many occurrences throughout the Pacific region may be misidentified as Paspalum distichum.

Habitat/ecology:  "Salt grass is pantropical in distribution, but is likely to have been an unintentional European introduction over most of its Pacific range.  In Micronesia it is found in nearly all the Micronesian archipelagoes, including the Marshall Islands (many atolls), where it appears to be a modern natural arrival.  [On Kwajalein} it is occasional to locally common in sunny coastal areas"  (Wagner & Steele, 1999; p. 88).  On Majuro, Marshall Islands, it is a "weedy plant forming dense patches near beaches and brackish marshy areas; often found in, or bordering, taro pits"  (Vander Velde, 2003; p. 52).  In Hawai‘i, "naturalized in coastal sites in shallow brackish water and on brackish sands, often forming pure stands at sea level"  (Wagner et al., 1999; p. 1578).  On Niue, "commonest on the more exposed south- and east-facing coasts"  (Sykes, 1970; p. 250).  On Guam, "usually near the sea or in brackish marshes, sometimes in mangrove regions"  (Stone, 1970: p. 217).  "In Fiji it is usually found near sea level...on beaches and creek banks and in mangrove swamps"  (Smith 1979; p. 336).

Propagation:  Seed

Native range:  "Native range unknown, now widely distributed in warm temperate to tropical sea coasts and brackish marshes worldwide" (Wagner et al., 1999; p. 1578).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	possibly native	Orchard, Anthony E., ed. (1994) (p. 12) "Although possibly native, this species has not, as far as is known, been recorded from the Island for about a century". Voucher cited: 1898, J.H. Maiden (K, NSW)
Cook Islands Northern Cook Islands	Nassau Island	native	McCormack, Gerald (2008)
Cook Islands Southern Cook Islands	Aitutaki Atoll	native	McCormack, Gerald (2008)
Cook Islands Southern Cook Islands	Mangaia Island	native	McCormack, Gerald (2008)
Cook Islands Southern Cook Islands	Rarotonga Island	native	McCormack, Gerald (2008)
Ecuador (Galápagos Islands) Isabela Group	Isabela Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	native	Charles Darwin Research Station (2005)
French Polynesia Marquesas Islands	Fatu Hiva Island	introduced invasive	Lorence, David H./Wagner, Warren L. (2008)
French Polynesia Marquesas Islands	Hiva Oa Island	introduced invasive	Lorence, David H./Wagner, Warren L. (2008)
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island	introduced invasive	Lorence, David H./Wagner, Warren L. (2008)
French Polynesia Marquesas Islands	Ua Huka (Huahuna, Uahuka) Island	introduced invasive	Lorence, David H./Wagner, Warren L. (2008)
French Polynesia Marquesas Islands	Ua Pou (Huapu, Uapou, Uapu) Island	introduced invasive	Lorence, David H./Wagner, Warren L. (2008)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1578)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1578)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Herbarium Pacificum Staff (1999) (p. 8) Voucher cited: C. Imada, K. Evans & M. Nishimoto 98-30
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Oppenheimer, Hank L. (2003) (p. 22) Voucher cited: Oppenheimer H110147 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1578) Voucher cited: Fosberg 13182 (BISH)
Marshall Islands Ralik Chain	Kili (Kõle) Atoll	introduced invasive	Vander Velde, Nancy/Vander Velde, Brian (2006) (p. 4) "Abundant to very abundant; along roadsides and in fields, forming large patches often dominating low-lying vegetation of wetland areas".
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54) As Palpalum distichum L.
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 88) Voucher cited: Fosberg 31189, Fosberg 31207, Fosberg 34123, Herbst 9051, Whistler 11162, Whistler 11196
Marshall Islands Ratak Chain	Arno Atoll	introduced invasive	Vander Velde, Nancy/Vander Velde, Brian (2007) (p. 3) "Uncommon to rare; patch near school in Ine observed from distance".
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54) As Palpalum distichum L.
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced invasive	Vander Velde, Nancy (2003) (p. 52)
Niue Niue	Niue Island	native	Sykes, W. R. (1970) (pp. 249-250) Vouchers cited: CHR 168741, CHR 168743
Philippines Philippine Islands	Philippine Islands		Waterhouse, D. F. (1993) (p. 67)
Philippines Philippine Islands	Philippine Islands		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 108)
Tuvalu Tuvalu (Ellis) Islands	Tuvalu Islands		Swarbrick, John T. (1997) (p. 95)

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)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 108)
Chile (continental) Chile	Chile (Republic of)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 108)
China China	China (People's Republic of)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 108)
Indonesia Indonesia	Indonesia (Republic of)		Waterhouse, D. F. (1993) (p. 67)
Indonesia Indonesia	Indonesia (Republic of)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 108)
Malaysia Malaysia	Malaysia (country of)		Waterhouse, D. F. (1993) (p. 67)
Mexico Mexico	Mexico (United Mexican States)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 108)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 570) "Coastal, often brackish, areas; often forming swards near edge of mud flats, or on sandy and shingly shores and occasionally spreading into pasture nearby".
Taiwan Taiwan	Taiwan Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 269)
Vietnam Vietnam	Vietnam (Socialist Republic of)		Waterhouse, D. F. (1993) (p. 67)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Indian Ocean offshore islands) Cocos (Keeling) Islands	Cocos (Keeling) Islands	native	Orchard, Anthony E., ed. (1993) (p. 39)
Maldives Maldive Islands	Malè Atoll		Fosberg, F. R. (1957) (p. 12) Voucher cited: Fosberg 36853 (US)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 269)

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

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

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

Other Latin names:  Palspalum distichum sensu auct. non L.

References:

Charles Darwin Foundation. 2008. Database inventory of introduced plant species in the rural and urban zones of Galapagos. Charles Darwin Foundation, Galapagos, Ecuador.

Charles Darwin Research Station. 2005. CDRS Herbarium records.

Edgar, E./Connor, H. 2000. Flora of New Zealand, vol. V: Gramineae. Manaaki Whenua Press. .

Fosberg, F. R. 1957. The Maldive Islands, Indian Ocean. Atoll Research Bulletin No. 58. Pacific Science Board, National Academy of Sciences, Washington. 37 pp.

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1987. A geographical checklist of the Micronesian monocotyledonae. Micronesica 20:1-126.

Hafliger, Ernst/Scholz, Hildemar. 1980. Grass weeds, vol. 1. CIBA-GEIGY Ltd., Basle, Switzerland. 142 pp. + plates.

Herbarium Pacificum Staff. 1999. New Hawaiian plant records for 1998. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1998. Part 1: Articles. Bishop Museum Occasional Papers. 58:3-11.

Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. 1979. A geographical atlas of world weeds. John Wiley & Sons, New York. 391 pp.

Lorence, David H./Wagner, Warren L. 2008. Flora of the Marquesas Islands. National Tropical Botanical Garden and the Smithsonian Institution. Online database.

McCormack, Gerald. 2008. Cook Islands Biodiversity Database, Version 2007.2. Cook Islands Natural Heritage Trust, Rarotonga.

Oppenheimer, Hank L. 2003. New plant records from Maui and Hawai‘i Counties. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2001-2002. Part 1: Articles. Bishop Museum Occasional Papers. 73:3-30.

Orchard, Anthony E., ed. 1993. Flora of Australia. Vol. 50, Oceanic islands 2. Australian Government Publishing Service, Canberra.

Orchard, Anthony E., ed. 1994. Flora of Australia. Vol. 49, Oceanic islands 1. Australian Government Publishing Service, Canberra.

Smith, Albert C. 1979. Flora Vitiensis nova: a new flora of Fiji. National Tropical Botanical Garden, Lawai, Kauai, Hawaii. Volume 1. 494 pp.

Stone, Benjamin C. 1970. The flora of Guam. Micronesica 6:1-659.

Swarbrick, John T. 1997. Weeds of the Pacific Islands. Technical paper no. 209. South Pacific Commission, Noumea, New Caledonia. 124 pp.

Sykes, W. R. 1970. Contributions to the flora of Niue. New Zealand Department of Scientific and Industrial Research Bulletin 200, Wellington. 321 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2009. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Vander Velde, Nancy. 2003. The vascular plants of Majuro Atoll, Republic of the Marshall Islands. Smithsonian Institution, Atoll Research Bulletin No. 503:1-141.

Vander Velde, Nancy/Vander Velde, Brian. 2006. Plants of Kili Island, Marshall Islands. Unpublished checklist. 12 pp.

Vander Velde, Nancy/Vander Velde, Brian. 2007. Arno plants [preliminary working listing of plant species]. Unpublished checklist, 13 pp.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Waterhouse, D. F. 1993. The major arthropod pests and weeds of agriculture in Southeast Asia. The Australian Centre for International Agricultural Research, Canberra. 141 pp.

Whistler, W. A./Steele, O. 1999. Botanical survey of the United States of America Kwajalein Atoll (USAKA) Islands. Prepared for Oak Ridge Institute for Science and Education and the U. S. Army Environmental Center. 111 pp.