Cyperus esculentus L., Cyperaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 19 (Go to the risk assessment).

Common name(s): [more details]

Chinese: you suo cao

English: chufa, earth almond, nutgrass, tigernut, watergrass, yellow nut grass, yellow nut grass, yellow nutsedge

French: amande de terre, choufa, souchet comestible

Spanish: cebollín, chufa, chufa commún, coco, coquillo, coquillo amarillo, coquito, coyolillo, juncia, juncia avellanada

Habit:  sedge

Description:  "Perennials with fibrous roots, stolons filiform, elongate, covered with pale brown scales, terminated by a small tuber; culms solitary, slender, trigonous, smooth, (10-) 25-50 cm tall, thickened at base with a small corm-like enlargement clothed with brown fibers.  Leaves basal, several per culm, blades linear, 3-6 mm wide, shorter than to longer than the culm; sheaths reddish brown; ligule absent.  Inflorescence an open umbelliform corymb, simple or partially compound, 4-7 cm long and as wide, primary rays slender, 5-8, spreading, 1-4 cm long, spikes ovoid, loosely bearing 5-14 spikelets; involucral bracts 3-6, leaf-like, spreading, the lower 1-2 surpassing the inflorescence; spikelets 8-16-flowered, yellowish brown or pale brown, linear-oblong to oblong, slightly compressed, 5-12 mm long, ca. 2 mm wide, rachilla winged; glumes yellowish brown or reddish brown, upper margins membranous, hyaline, ovate or ovate-elliptic, 1.6-2.2 mm long, 7-nerved, apex and keel obtuse; stigmas 3.  Achenes grayish brown, glossy, obovate or oblong-obovate, obtusely trigonous, 1.5-1.8 mm long, minutely puncticulate.  Separation of this species from the very similar Cyperus rotundus is often difficult.  Cyperus eesculentus is generally larger than C. rotundus, and the glumes of the former are yellow rather than reddish brown in the latter.  The most reliable character, however, is the presence of a short ligule on the leaves of C. rotundus; this is absent on the leaves of C. esculentus"  (Wagner et al., 1999; p. 1396).

Habitat/ecology:  "The weed is found on low ground, moist fields, in heavily irrigated crops, along river banks and roadsides, and in ditches.  It tolerates high soil moisture much better than does C. rotundus.  The species grows very well on all soil types, including black peat soils, and performs equally well at pH ranges from 5 to 7.  It is quite intolerant of shade"  (Holm et al., 1977; pp. 125-133).

In New Zealand, "a weedy plant, troublesome overseas in gardens and cultivated land" (Healy & Edgar, 1980; p. 186).

Propagation:  Seed

Native range:  "Southern Europe, Mediterranean region, South Africa, North America, and the Andean region of South America" (Wagner et al., 1999; p. 1396).

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	Hawai‘i (Big) Island	introduced invasive	Strong, Mark T./Wagner, Warren L. (1997) (p. 41) Voucher cited: Stemmermann 6889 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wood, K. R. (2006) (p. 17) Voucher cited: K.R. Wood & S. Perlman 5103 (AD, BISH, F, K, MO, NY, PTBG, US)

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)	New South Wales		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
Australia Australia (continental)	Queensland	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
Cambodia Cambodia	Cambodia (Kingdom of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
Chile (continental) Chile	Chile (Republic of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
China China	China (People's Republic of)		Hafliger, E. (1092) (p. 18)
Colombia Colombia	Colombia (Republic of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
Indonesia Indonesia	Indonesia (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 114)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 193)
Mexico Mexico	Mexico (United Mexican States)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Healy, A. J./Edgar, E. (1980) (p. 186) Voucher cited: G. S. Harris (CHR 83385)
Nicaragua Nicaragua	Nicaragua (Republic of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 127, 133)
Perú Perú	Perú (Republic of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
Taiwan Taiwan	Taiwan Island	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 127)
Thailand Thailand	Thailand (Kingdom of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 133)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		McIntyre, Guy (1991) (p. 47)

Additional information:
Draft European and Mediterranean Plant Protection Organization datasheet.

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

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

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

References:

Hafliger, E. 1092. Monocot Weeds 3. CIBA-GEIGY Ltd., Basle, Switzerland. 132 pp. plus plates.

Healy, A. J./Edgar, E. 1980. Flora of New Zealand, Volume III: Adventive cyperaceous, petalous & spathaceous monocotyledons. Government Printer, Wellington, New Zealand. 220 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.

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.

McIntyre, Guy. 1991. Weeds of sugar cane in Mauritius, their description and control. Mauritius Sugar Industry Reseach Institute. 151 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.

Strong, Mark T./Wagner, Warren L. 1997. New and noteworthy Cyperaceae from the Hawaiian Islands. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1996. Part 1: Articles. Bishop Museum Occasional Papers. 48:37-50.

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

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).

Wood, K. R. 2006. New plant records and rediscoveries within the Hawaiian Islands. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 2: Notes. Bishop Museum Occasional Papers 88:15-19.

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