Echinochloa crus-galli (L.) P.Beauv., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Panicum crus-galli L.

Common name(s): [more details]

Bikol: lagtom

Bontoc: sasablog

Chinese: bai

English: barnyard grass, baronet grass, cockspur grass, water grass

French: bourgon, crête de coq, ergot de coq, millard, pattes de poule, pied de coq

Ifugao: baobao

Japanese: ta-in-ubie

Manobo: dauana

Spanish: arrocillo, barbarroja, cola de caballo, hualcacho, jaraz fina, mijo japonés, pagarropa, panicello, pasto rayado, pata de gallo, pie de gallina, pierna o pata de gallo, zacate de agua

Tagalog: bayokibok, daua-daua

Habit:  grass

Description:  "Annuals, culms stout, tufted, ascending in upper part, (1.5-) 3-10 (-14) dm tall, geniculate and decumbent below, glabrous, leafy.  Sheaths glabrous; ligule absent; blades flat, 4-12 (-16) mm wide, margins scabrous, a few papillae near the collar, these sometimes with hairs.  Inflorescences paniculate, erect or nodding, 5-12 (20) racemosely arranged lateral branches; spikelets 2.8-3.5 mm long, somewhat turgid to laterally compressed, apex acuminate to awned; first glume broad, 1.2-1.6 mm long, clasping, 3-nerved, scaberulous, apex apiculate to caudate, sometimes with an awn up to 0.5 mm long, second glume 2.5-3.2 mm long, 5-nerved, the lateral nerves pectinate near the margins and scabrous toward base, apex acuminate or with an awn 0.7-1.5 mm long; first lemma awned, the awn 0.5-30 mm long, palea usually well-developed, second lemma indurate, plano-convex, 2.2-3 (-3.3) mm long, smooth and glossy, 5-9-nerved, apex abruptly acute, awned, the awn up to 0.5 mm long; palea similar in texture to lemma.  Caryopsis pale brown, suborbicular or ovoid, 1.4-2 mm long, 1.2-1.6 mm in diameter"  (Wagner et al., 1999; p. 1535).

Description from GrassBase.

A closely related species, also invasive, is Echinochloa crus-pavonis.  It is often difficult to distinguish from E. crus-galli.  The rather soft, pinkish, or pale purple panicle with crowded spikelets with very long awns is characteristic of E. crus-pavonis (Holm et al., 1977; p. 32).

Habitat/ecology:  "The weed prefers wet soils and can continue to grow when partially submerged.  On occasion it has been described as a weed of swamps and aquatic places.  In drier soils it is not as tall and the yield of seeds and the numbers of panicles and tillers are reduced.  It is normally found only at low and medium altitudes.  It grows best in rich, moist soils with a high nitrogen content, but it can also thrive on sands and loamy soils" (Holm et al., 1977; p. 35).

In Hawai‘i, "naturalized in wet or seasonally wet sites such as ditches or stream beds, and in cultivated fields, 0-520 m" (Wagner et al., 1999; p. 1535). In Fiji, "occurring near sea level in rice fields, swampy places, and along roadsides" (Smith, 1979; pp. 341-342). In New Caledonia, "Peut-être d'introduction pré-européenne. Largement répandu en stations humides. Semble d'après les spécimens nombreux avoir été plus abondant au 19e siècle qu'à présent" (MacKee, 1994; p. 59).

Propagation:  Seed.  "Some seeds germinate immediately, although others remain viable for several years"  (Waterhouse, 1994; p. 62).

Native range:  "Common in many subtropical and temperate areas" (Smith, 1979; pp. 341-342).

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	introduced	Pickard, J. (1984) (p. 205)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 22) "As elsewhere in the warm temperate and tropical regions of the world, this is a weed of cultivated land and open ground". Voucher cited: A.C. Beauglehole 5449 (CANB)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 12) "As elsewhere in the warm temperate and tropical regions of the world, this is a weed of cultivated land and open ground". Vouchers cited: W.R. Sykes NI 69 (CHR); W. Laing (CHR); E. Ralston 38 (CHR); E. Ralston 39 (CHR); a long awned variant, W. Laing (CHR); Nov. 1898, I. Robinson(NSW)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced invasive cultivated	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive cultivated	Charles Darwin Foundation (2008)
Federated States of Micronesia Yap Islands	Faraulep (Faraulap) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 41) var. hispidula
Federated States of Micronesia Yap Islands	Faraulep (Faraulap) Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (p. 48) Var. austro-japonensis; voucher cited: Fosberg & Evans 47372 (US, BISH, CANB, L).
Federated States of Micronesia Yap Islands	Ifalik (Ifaluk) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 41) var. hispidula
Federated States of Micronesia Yap Islands	Ifalik (Ifaluk) Atoll	introduced	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 47-48) Var. hispidula; vouchers cited: Abbott & Bates 69 (US), Abbott & Bates 119 (US), Abbott & Bates 128 (US)
Federated States of Micronesia Yap Islands	Ulithi Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 41) var. austro-japonensis and var. hispidula
Federated States of Micronesia Yap Islands	Ulithi Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 47-48) Var. austro-japonensis; voucher cited: Fosberg & Wong 25500 (US); var. hispidula; voucher cited: Fosberg 46503 (US, BISH)
Federated States of Micronesia Yap Islands	Woleai Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 41) var. hispidula
Federated States of Micronesia Yap Islands	Woleai Atoll	introduced	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 47-48) Var. hispidula; vouchers cited: Evans 513 (US, BISH, POM, BRI), Fosberg 47026 (US, BISH)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 41) var. hispidula
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 47-48) Var. hispidula; voucher cited: Wong 400 (US)
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1979) (pp. 341-342) var. hispidula. Vouchers cited: DA 8632, DA 3974, DA 3562, DA 3577, DA 3579, DA 7522, DA 3096, DA 11234, Meebold 26533
French Polynesia Society Islands	Moorea Island	introduced invasive	Welsh, S. L. (1998) (p. 335) Voucher cited: Grant 5363
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) subsp. hispidula (A.J. Retzius) M. Honda Adventice
French Polynesia Austral (Tubuai) Islands	Raivavae (Raevavae) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Voucher cited: J. Florence & W.R. Sykes 11182 (PAP) Adventice
French Polynesia Austral (Tubuai) Islands	Rurutu Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Voucher cited: J. Florence 6204 (PAP) Adventice
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1535)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1535)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1535)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1535)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1535)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1535) Voucher cited: Didrichsen s.n. (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Herbst, Derral R./Clayton, W. D. (1998) (p. 24) Voucher cited: Hosaka 1378 (BISH)
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands		Kato, Hidetoshi (2007) Also var. formosensis Ohwi
Kiribati Tungaru (Gilbert) Islands	Butaritari Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 40) var. austro-japonensis
Kiribati Tungaru (Gilbert) Islands	Butaritari Atoll	introduced	Fosberg, F. R./Sachet, M.-H. (1982) (p. 48) Var. austro-japonensis; voucher cited: Herbst & Allerton 2698 9US)
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 40) Var. austro-japonensis
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (p. 48) Var. austro-japonensis; voucher cited: Fosberg 39464 (US)
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1962) (p. 5) On Pinlep Islet. Vouchers cited: Fosberg 39464 (US), Fosberg 41407 (US)
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Ouvéa (Ouvea Atoll)	introduced invasive abo. intro.	Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 380) Largement répandue en stations humides. Semble avoir été plus abondante au 19è siècle qu'à présent.
New Caledonia Îles Loyauté (Loyalte Islands)	Îles Ouvéa (Ouvea Atoll)	introduced invasive abo. intro.	MacKee, H. S. (1994) (p. 59)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive abo. intro.	Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 380) Largement répandue en stations humides. Semble avoir été plus abondante au 19è siècle qu'à présent.
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive abo. intro.	MacKee, H. S. (1994) (p. 59) Voucher cited: MacGillivray 33
New Caledonia New Caledonia Archipelago	Île des Pins (Isle of Pines)	introduced invasive abo. intro.	Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 380) Largement répandue en stations humides. Semble avoir été plus abondante au 19è siècle qu'à présent.
New Caledonia New Caledonia Archipelago	Île des Pins (Isle of Pines)	introduced invasive abo. intro.	MacKee, H. S. (1994) (p. 59)
Niue Niue	Niue Island	introduced	Sykes, W. R. (1970) (pp. 241-242) Voucher cited: CHR 156828
Palau Palau (main island group)	Babeldaob Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 41) var. hispidula
Palau Palau (main island group)	Babeldaob Island	introduced	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 47-48) Var. hispidula; voucher cited: Takamatsu 1386 (US, BISH)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Henty, E. E. (1969) (p. 81) A weed of cultivation in the tropics; in New Guinea from sea level to 7,000 ft.
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced	Waterhouse, D. F. (1997) (p. 61)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1925) (p. 63) At low and medium altitudes, in open wet places, rice paddies, etc.
Solomon Islands Solomon Islands	Solomon Islands	introduced	Hancock, I. R./Henderson, C. P. (1988) (p. 70)
United States (other Pacific offshore islands) Johnston Atoll	Johnston Island	introduced invasive	Amerson, A. Binion, Jr./Shelton, Philip C. (1976) (p. 52)
United States (other Pacific offshore islands) Midway Atoll	Midway Atoll	introduced invasive	Starr, Forest/Martz, Kim/Loope, Lloyd L. (2002) (p. 22) Voucher cited: Starr & Martz 990620-1 (BISH)
Wallis and Futuna Wallis and Futuna (Horne) Islands	Wallis and Futuna Islands	introduced	Waterhouse, D. F. (1997) (p. 61)

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)	Queensland	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 39)
Cambodia Cambodia	Cambodia (Kingdom of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)
Chile (continental) Chile	Chile (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 39-40)
China China	China (People's Republic of)		Li-ying, Li/Ren, Wang/Waterhouse, D. F. (1997) (p. 172)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 333) In marshes, ditches and paddy fields.
Colombia Colombia	Colombia (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 39-40)
Costa Rica Costa Rica	Costa Rica (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 133)
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)
Japan Japan	Japan (country)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 39-40)
South Korea South Korea	South Korea (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 133)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)
Mexico Mexico	Mexico (United Mexican States)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 39-40)
Negara Brunei Darussalam Brunei	Brunei (Negara Brunei Darussalam)	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 546) "Waste land, cultivated land, often coastal and sometimes in swampy ground".
Perú Perú	Perú (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 39-40)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)
Singapore Singapore	Singapore (Republic of)	uncertain if introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 37) Weed of uncertain origin
Taiwan Taiwan	Taiwan Island		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (pp. 39-40)
Thailand Thailand	Thailand (Kingdom of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 65, 77)

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		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 133)

Comments:  Apparently introduced to Niue with pasture grass seed (Sykes, 1970; pp. 241-242). Not seen in recent surveys.

Control: 

Biological:  Waterhouse (1994, pp. 63-66) lists natural enemies of the species.

Additional information:
Additional online information about Echinochloa crus-galli is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Echinochloa crus-galli as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Echinochloa crus-galli may be available from the Germplasm Resources Information Network (GRIN).

References:

Amerson, A. Binion, Jr./Shelton, Philip C. 1976. The natural history of Johnston Atoll. Atoll Research Bulletin No. 192. Smithsonian Institution, Washington. 479 pp.

Cardenas, Juan/Reys, Carlos E./Doll, Jerry D./Pardo, Fernando. 1972. Tropical weeds; malezas tropicales, vol. 1. International Plant Protection Center, Oregon State University, Corvallis. 341 pp.

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.

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.

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

Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. 2011. Base de données botaniques Nadeaud de l'Herbier de la Polynésie Française (PAP). (online resource).

Fosberg, F. R./Sachet, M.-H. 1962. Vascular plants recorded from Jaluit Atoll. Atoll Research Bulletin No. 92. Pacific Science Board, National Academy of Sciences, Washington. 39 pp.

Fosberg, F. R./Sachet, M.-H. 1982. Micronesian Poaceae: Critical and distributional notes. Micronesica 18(2):45-102.

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

Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe. 1996. Conséquences des introductions d'espèces animales et végétales sur la biodiversité en Nouvelle-Calédonie. Rev. Ecol. (Terre Vie) 51:375-401.

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

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

Henty, E. E. 1969. A manual of the grasses of New Guinea. Department of Forests, Division of Botany, Botany Bull. No. 1. Lae, New Guinea. 215 pp.

Herbst, Derral R./Clayton, W. D. 1998. Notes on the grasses of Hawai‘i: new records, corrections, and name changes. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1997. Part 1: Articles. Bishop Museum Occasional Papers. 55:17-38.

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.

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

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.

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.

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

Pickard, J. 1984. Exotic plants on Lord Howe Island: Distribution in space and time, 1853-1981. J. of Biogeography 11:181-208.

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

Starr, Forest/Martz, Kim/Loope, Lloyd L. 2002. New plant records from the Hawaiian archipelago. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2000. Part 2: Notes. Bishop Museum Occasional Papers. 69:16-27.

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. 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).

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.

Waterhouse, D. F. 1994. Biological control of weeds: Southeast Asian prospects. Australian Centre for International Agricultural Research, Canberra. 302 pp.

Waterhouse, D. F. 1997. The major invertebrate pests and weeds of agriculture and plantation forestry in the Southern and Western Pacific. The Australian Centre for International Agricultural Research, Canberra. 93 pp.

Welsh, S. L. 1998. Flora Societensis: A summary revision of the flowering plants of the Society Islands. E.P.S. Inc., Orem, Utah. 420 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).