Paspalum distichum L., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Paspalum paspalodes (Michx.) Scribn.

Common name(s): [more details]

Chinese: shuang sui que bai

English: couch paspalum, eternity grass, ginger grass, joint grass, knotgrass, knotroot paspalum, mercer grass, seaside millet, Thompson grass, water couch

Fijian: kambutu

Niuean: mosi kalalahi

Pohnpeian: dimwir, timur

Spanish: grama colorada, gramilla blanca

Tahitian: matie

Habit:  grass

Description:  "Habit: Perennial; mat forming. Stolons present. Culms decumbent; 8-60 cm long. Ligule an eciliate membrane. Leaf-blades flat, or convolute; 3-14 cm long; 3-7 mm wide. Inflorescence composed of racemes. Racemes 2(-3); paired; unilateral; 2-8 cm long. Rhachis narrowly winged; angular. Spikelet packing abaxial; regular; 2 -rowed. Spikelets solitary. Fertile spikelets sessile. Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; turgidly plano-convex; acute; 3-4 mm long; falling entire. Glumes one the lower absent or obscure, or two (rarely); reaching apex of florets; thinner than fertile lemma. Lower glume when present ovate; 0.1-0.2 times length of spikelet; hyaline; 0 -veined. Lower glume lateral veins absent. Upper glume elliptic; 1 times length of spikelet; coriaceous; without keels; 3 -veined. Upper glume surface puberulous. Upper glume apex acute. Florets: Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; elliptic; 1 times length of spikelet; coriaceous; 3 -veined; acute. Fertile lemma ovate; gibbous; 2.5 mm long; indurate; pallid; without keel. Lemma margins involute. Lemma apex acute. Palea involute; indurate"  (GrassBase).

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

Habitat/ecology:  "Heath- and shrubland, riparian habitats, freshwater wetlands.  Within the native range, this C4 grass is found in sands and muds near the seashore, in saline soils and swamps.  The grass forms dense mats of stolons and shallow rhizomes, outcompeting and displacing native vegetation"  (Weber, 2003; p. 305).

Propagation:  Seed and vegetatively. "The grass spreads mainly vegetatively.  Pieces of stolons easily root and form new plants.  Seeds remain viable in water for some while and are carried by streams long distances to start new infestations"  (Weber, 2003; p. 305).

Native range:  "It probably originates from tropical South America but the exact native range is obscure"  (Weber, 2003; p. 305).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
American Samoa Manu‘a Islands	Ta‘u Island		Whistler, W. A. (1979) (p. 276)
American Samoa Tutuila Islands	Aunu‘u Island		Whistler, W. A. (1979) (p. 276)
American Samoa Tutuila Islands	Tutuila Island		Whistler, W. A. (1979)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	native	Orchard, Anthony E., ed. (1994) (p. 12) Voucher cited: J. Pickard 2716 (NSW)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 556)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Anatahan Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Pagan Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Saipan Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Chuuk Islands	Dublon (Tonowas) Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Chuuk Islands	Fefan Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Chuuk Islands	Lukunor (Núkúnooch) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Chuuk Islands	Namoluk (Nómwunuuk) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Chuuk Islands	Param Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Chuuk Islands	Satawan Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Kosrae Island	Kosrae Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 90)
Federated States of Micronesia Pohnpei Islands	Kapingamarangi Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Pohnpei Islands	Mokil Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Pohnpei Islands	Nukuoro Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Pohnpei Islands	Pingelap Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 90)
Federated States of Micronesia Yap Islands	Fais Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Yap Islands	Ifalik (Ifaluk) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Yap Islands	Ulithi Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Yap Islands	Woleai Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 90)
Fiji Fiji Islands	Kandavu Island	native	Smith, Albert C. (1979) (p. 336) Vouchers cited: C. R. Turbet 4, DA 2970
Fiji Fiji Islands	Lakemba Island	native	Smith, Albert C. (1979) (p. 336) Voucher cited: Garnock-Jones 941
Fiji Fiji Islands	Vanua Levu Island	native	Smith, Albert C. (1979) (p. 336) Voucher cited: DA 16688
Fiji Fiji Islands	Viti Levu Island	native	Smith, Albert C. (1979) (p. 336) Vouchers cited: Greenwood 227, DA 11706, DA 10125, DA 2346, DA 3965, DA 7759, DA 10061, DA L.11451, DA L.16688
Guam Guam Island	Guam Island	native	Stone, Benjamin C. (1970) (p. 217)
Guam Guam Island	Guam Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Herbst, Derral R./Wagner, Warren L. (1999) (p. 28) Voucher cited: Herbst 5954 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Herbst, Derral R./Wagner, Warren L. (1999) (p. 28) Vouchers cited: Dillingham s.n. (BISH 120043), Dillingham s.n. (BISH 120044)
Kiribati Tungaru (Gilbert) Islands	Butaritari Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Kiribati Tungaru (Gilbert) Islands	Marakei Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Kiribati Tungaru (Gilbert) Islands	Nikunau Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Marshall Islands Ralik Chain	Ailinglaplap (Ailinglapalap) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Marshall Islands Ratak Chain	Ailuk (Aelok) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Marshall Islands Ratak Chain	Arno Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Marshall Islands Ratak Chain	Likiep Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Palau Hatohobei Group	Tobi Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Palau Hatohobei Group	Tobi Island		Beleu National Museum (Republic of Palau. Koror.) (1970) (voucher ID: BNM 148) Taxon name on voucher: Paspalum distichum L.
Palau Palau (main island group)	Angaur Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Palau Palau (main island group)	Angaur Island	native	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. Field notes)
Palau Palau (main island group)	Angaur Island		Beleu National Museum (Republic of Palau. Koror.) (1977) (voucher ID: BNM 911) Taxon name on voucher: Paspalum distichum L.
Palau Palau (main island group)	Babeldaob Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Palau Palau (main island group)	Koror Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Palau Palau (main island group)	Koror Island	native	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. Field notes)
Palau Palau (main island group)	Koror Island		Beleu National Museum (Republic of Palau. Koror.) (1977) (voucher ID: BNM 10009) Taxon name on voucher: Paspalum distichum L.
Palau Palau (main island group)	Ngerkebesang Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Palau Palau (main island group)	Peleliu Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)
Philippines Philippine Islands	Philippine Islands		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
United States (other Pacific offshore islands) Wake Islands	Wake Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 54)

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)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Chile (continental) Chile	Chile (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
China China	China (People's Republic of)		Li-ying, Li/Ren, Wang/Waterhouse, D. F. (1997) (p. 174)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 342) As Paspalum paspaloides (Michx.) Scribn. On farmlands.
Colombia Colombia	Colombia (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
El Salvador El Salvador	El Salvador (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
Honduras Honduras	Honduras (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
Japan Japan	Japan (country)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 192) var. distichum and var. indutum Shinners
Malaysia Malaysia	Malaysia (country of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
Mexico Mexico	Mexico (United Mexican States)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2011)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 567) "Damp soil at lake edges, sand flats, swampy roadsides, waste ground, also a weed of lawns and cultivated ground - often in fresh, not brackish water".
Taiwan Taiwan	Taiwan Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mascarene Islands Mascarene Islands (Mauritius, La Reunion, Rodrigues)	Mascarene Islands	introduced	Weber, Ewald (2003) (p. 305)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 267)
Seychelles Seychelles Islands	Agalega Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Stoddart, D. R. (1983) (p. 132)

Control: 

Physical:  "Cutting close to the ground reduces stolon and rhizome growth but does not kill the plant".

Chemical:  "An effective herbicide is glyphosate"  (Weber, 2003; p. 305).

Additional information:
Information from the Fire Effects Information System.

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

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

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

References:

Atkinson, Rachel/Sawyer, John. 2011. Naturalized species in the Juan Fernández Archipelago, Chile. Unpublished spreadsheet.

Beleu National Museum (Republic of Palau. Koror.). 1970. Voucher specimen #BNM148(Salsedo, Carl A. 384).

Beleu National Museum (Republic of Palau. Koror.). 1977. Voucher specimen #BNM911(Canfield, J.E. 197).

Beleu National Museum (Republic of Palau. Koror.). 1977. Voucher specimen #BNM10009(Otobed, D.O. PW-10009).

Clayton, W.D./Harman, K.T./Williamson, H. 2011. World Grass Species: Descriptions, Identification, and Information Retrieval [GrassBase - The Online World Grass Flora]. The Board of Trustees, Royal Botanic Gardens, Kew.

Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido. 2006. Nouveau catalogue de la flore vaculaire de l'archipel Juan Fernández (Chile) [Nuevo catálogo de la flora vacular del Archipélago Juan Fernández (Chile)]. Acta Bot. Gallica 153(4):399-587.

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

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

Fosberg, F. R./Sachet, Marie-Hélène/Stoddart, D. R. 1983. List of the recorded vascular flora of Agalega. In: Sachet, M. H., D. R. Stoddart, and F. R. Fosberg. Floristics and ecology of Western Indian Ocean islands. Atoll Research Bulletin No. 273. Smithsonian Institution, Washington. 253 pp.

Herbst, Derral R./Wagner, Warren L. 1999. Contributions to the flora of Hawai‘i. VII. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1998. Part 1: Articles. Bishop Museum Occasional Papers. 58:12-36.

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.

Li-ying, Li/Ren, Wang/Waterhouse, D. F. 1997. The distribution and importance of arthropod pests and weeds of agriculture and forestry plantations in southern China. ACIAR, Canberra, Australia. 185 pp.

Merlin, M./Jano, D./Raynor, W./Keene, T./Juvik, J./Sebastian, B. 1992. Tuhke en Pohnpei: Plants of Pohnpei. Environment and Policy Institute, East-West Center, Honolulu, Hawai‘i, 94 pp. .

Meyer, Jean-Yves. 2000. Preliminary review of the invasive plants in the Pacific islands (SPREP Member Countries). In: Sherley, G. (tech. ed.). Invasive species in the Pacific: A technical review and draft regional strategy. South Pacific Regional Environment Programme, Samoa. 190 pp.

Mito, Toshikazu/Uesugi, Tetsuro. 2004. Invasive alien species in Japan: the status quo and the new regulation for prevention of their adverse effects. Global Environmental Research 8(2)/2004: 171-191.

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.

Space, James C./Lorence, David H./LaRosa, Anne Marie. 2009. Report to the Republic of Palau: 2008 update on Invasive Plant Species. USDA Forest Service, Hilo, Hawai‘i. 227 pp.

Stemmermann, Lani. 1981. A guide to Pacific wetland plants. U. S. Army Corps of Engineers, Honolulu District. 118 pp.

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

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.

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.

Whistler, W. A. 1979. A study of the vegetation of eastern Samoa. A dissertation submitted to the graduate division of the University of Hawaii in partial fulfillment of requirements for the degree of Doctor of Philosophy in Botanical Sciences. 325 pp.

Whistler, W. A. 1980. Coastal flowers of the tropical Pacific: A guide to widespread seashore plants of the Pacific Islands. National Tropical Botanical Garden. Lawai, Hawaii. 83 pp. ISBN 0-932596-13-14.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).