Cyperus iria L., Cyperaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Bikol: taga-taga

Bontoc: okoiang

Chinese: sui mi suo cao

English: grasshopper's cyperus, rice flat sedge, ricefield flatsedge, umbrella sedge

Filipino: alinang, paiung-paiung

Japanese: kogomegawatsuri

Palauan: badel aus

Tahitian: mou, mou hairi

Habit:  sedge

Description:  "Cespitose herb, culms to 50 cm tall, few leaves; leaves shorter than culm; bracts longer than inflorescence; inflorescence branched, spikes about 2.5 cm long, about 10-12-flowered; spikelets 6 mm long, glumes spreading, scarcely imbricate, apex rounded with a tiny mucro, pale straw-colored, but green-carinate; achene narrowly obovoid, yellow-brown, trigonal, minutely apiculate"  (Stone, 1970; P. 167).

"Annual, with fibrous roots only; culms solitary or a few together, erect, 8-60 cm tall, slender or slightly thick, trigonous, smooth; leaves 2 or 3 to a culm, much shorter than culm; blades linear, 2-5 mm broad, weakly folded; sheaths reddish or somewhat purplish brown; corymbs as a rule compound, 5-15 cm long, 3-10 cm broad, with 3-7 unequal rays 2-12 cm long, each bearing 5-10 spikes; spikes often more or less inclined, elliptic-ovate, 1-4 cm long, bearing 4-20 spikelets; leafy bracts 4 or 5, the lowest 2 or 3 surpassing the corymb; spikelets rather loosely disposed, erect-patent, oblong-elliptic or lanceolate, 4-9 mm long, 1.7-2 mm broad, flattened, 6-22-flowered; rhachilla hardly winged; glumes subloosely disposed, obovate-orbicular, 1-1.5 mm long, truncate to shallowly retuse at the usually nucronulate apex, thinly herbaceous, yellow or slightly straw-colored, pale on hyaline upper margin, 3- or 5-nerved, convex on the green keel; achenes obovate, 3-sided, nearly equalling the glume, maturing dark brown; style short, about 1/3 as long as achene; stigmas 3, stamens 3" (Smith, 1979; pp. 250-251).

Illustration by International Rice Research Institute (IRRI) courtesy Ecoport.

Habitat/ecology:  "It is mainly a weed of open, wet places"  (Holm et al., 1977; p. 240).  In Fiji, "a naturalized adventive, often locally abundant on Viti Levu from sea level to 300 m, along roadsides and in swamps, cultivated areas, and especially in rice fields" (Smith, 1979; pp. 250-251).

Propagation:  Seed

Native range:  "East Africa and central Asia through India to China and Japan, eastward to Malesia and Australia" (Smith, 1979; pp. 250-251).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Saipan Island	native	Raulerson, L. (2006) (p. 13)
Federated States of Micronesia Chuuk Islands	Weno (Moen) Island	native	Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane/Mazawa, Thomas R. (2000) (p. Voucher specimen) Voucher: BMW 5788 (BISH, BRI)
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1979) (pp. 250-251) Vouchers cited: Greenwood 806B, DA 10556, DA 2845, DA 7818, DA 7987, DA 8685, DA 6093, DA 8617
Guam Guam Island	Guam Island	native invasive	Stone, Benjamin C. (1970) (p. 167) Voucher cited: Necker 68
Guam Guam Island	Guam Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 66)
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands	introduced	Kato, Hidetoshi (2007)
Nauru Nauru Island	Nauru Island	introduced invasive	Thaman, R. R./Fosberg, F. R./Manner, H. I./Hassall, D. C. (1994) (p. 50) Voucher cited: Thaman & Manner 90a (SUVA) Rare
New Caledonia New Caledonia	New Caledonia Islands		Swarbrick, John T. (1997) (p. 90)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	Tassin, Jacques (2005)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced	MacKee, H. S. (1994) (p. 48) Vouchers cited: MacKee 28356, MacKee 29833, MacKee 36714
Palau Palau (main island group)	Babeldaob Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 66)
Palau Palau (main island group)	Koror Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 66)
Palau Palau (main island group)	Malakal Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 66)
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. (2011)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1925) (p. 106) In open wet places; a common and characteristic rice paddy weed.
Solomon Islands Solomon Islands	Solomon Islands		Swarbrick, John T. (1997) (p. 90)
Solomon Islands Solomon Islands	Solomon Islands	native	Hancock, I. R./Henderson, C. P. (1988) (p. 62)

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)	Northern Territory	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Australia Australia (continental)	Queensland	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Cambodia Cambodia	Cambodia (Kingdom of)	native	Waterhouse, D. F. (1993) (pp. 64, 77)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 310) In wet places and paddy fields.
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Japan	Japan (country)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Ryukyu Islands	Ryukyu Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
South Korea South Korea	South Korea (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Negara Brunei Darussalam Brunei	Brunei (Negara Brunei Darussalam)	native	Waterhouse, D. F. (1993) (pp. 64, 77)
Singapore Singapore	Singapore (Republic of)	native	Waterhouse, D. F. (1993) (pp. 64, 77)
Singapore Singapore	Singapore (Republic of)	uncertain if introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 31) Weed of uncertain origin
Taiwan Taiwan	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Thailand Thailand	Thailand (Kingdom of)	native	Waterhouse, D. F. (1993) (pp. 64, 77)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	Waterhouse, D. F. (1993) (pp. 64, 77)

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) Christmas Island Group	Christmas Island	extirpated	Swarbrick, J. T. (1997) (p. 111)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island		Topp, J. M. W. (1988) (p. 18)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island	introduced invasive	Whistler, W. Arthur (1996) (p. 23)

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

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

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

References:

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

Fosberg, F. R./Otobed, D./Sachet, M.-H./Oliver, R. L./Powell, D. A./Canfield, J. E. 1980. Vascular plants of Palau with vernacular names. Department of Botany, The Smithsonian Institution, Washington, D.C. 43 pp.

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

Hancock, I. R./Henderson, C. P. 1988. Flora of the Solomon Islands. Research Bulletin No. 7. Ministry of Agriculture and Lands, Honiara. 203 pp.

Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. 1977. The world’s worst weeds: distribution and biology. East-West Center/University Press of Hawaii. 609 pp.

Kato, Hidetoshi. 2007. Herbarium records of Makino Herbarium, Tokyo Metropolitan University. Personal communication.

MacKee, H. S. 1994. Catalogue des plantes introduites et cultivées en Nouvelle-Calédonie. Muséum National d'Histoire Naturelle, Paris, 164 p.

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

Raulerson, L. 2006. Checklist of Plants of the Mariana Islands. University of Guam Herbarium Contribution 37:1-69. .

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./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane/Mazawa, Thomas R. 2000. Invasive plant species in Chuuk, Federated States of Micronesia.  USDA Forest Service, Honolulu. 41 pp.

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

Swarbrick, J. T. 1997. Environmental weeds and exotic plants on Christmas Island, Indian Ocean: a report to Parks Australia. 101 pp. plus appendix.

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

Tassin, Jacques. 2005. Jacques Tassin (IAC-CIRAD), personal communication.

Thaman, R. R./Fosberg, F. R./Manner, H. I./Hassall, D. C. 1994. The flora of Nauru. Smithsonian Institution, Washington. Atoll Research Bulletin 392:1-223.

Topp, J. M. W. 1988. An annotated check list of the flora of Diego Garcia, British Ocean Territory. Atoll Research Bulletin No. 313. Smithsonian Institution, Washington. 21 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

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. Arthur. 1996. Botanical survey of Diego Garcia, Chagos Archipelago, British Indian Ocean Territory. Isle Botanica. 49 pp.

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).