Sorghum bicolor (L.) Moench, Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Evaluate, score: 5 (Go to the risk assessment (Australia))
Low risk (based on second screen), score: 6 (Go to the risk assessment (Pacific)).
High risk (ssp. drummondii), score: 17.5 (Go to the risk assessment (Pacific)).
Reject (grain sorghum), score: 7 (Go to the risk assessment (U.S. (Florida))).
Reject (shattercane), score: 18 (Go to the risk assessment (U.S.(Florida))).
Accept (sweet) (based on second screen), score: 3 (Go to the risk assessment (U.S.)).
Accept (sweet) (based on second screen), score: 2 (Go to the risk assessment (U.S. (Florida))).

Other Latin names:  Holcus bicolor L.; Sorghum sudanense (Piper) Stapf [= Sorghum bicolor nothosubsp. drummondii]

Common name(s): [more details]

Chinese: gao liang

English: broom corn, durra, forage sorghum, gooseneck sorgho, grain sorghum, great millet, Kaffir-corn, milo, shallu, shattercane, sweet sorghum, wildcane

French: gros mil, sorgho, sorgho vulgaire

Maori (Cook Islands): tarapi

Marshallese: korn

Spanish: daza, maiz milo, mijo, millo, sorgo, sorgo forrajero

Tongan: kola

Habit:  grass

Description:  "Annual with broad blades up to 30-60 cm long, 4-8 cm wide; the midrib prominent and pale; panicle stiffly erect; sessile spikelets broadly obovate 4-5.5 mm long, 3-4.5 mm wide, subglobose at maturity; upper lemma awned; glumes coriaceous; caryopsis plump, about 4 mm long, barely as broad, yellow to orange or reddish, exposed distally."  (Stone, 1970)"Robust annuals; culms 10-30 dm tall, nodes puberulent to short-pilose.  Sheaths glabrous, compressed, keeled; ligule chartaceous, 1.5-5.5 mm long, apex rounded, ciliate; blades flat, (12-) 20-40 (-52) mm wide, midrib well-developed, margins scabrous.  Panicles dense and compact, 10-25 (-35) cm long, branches numerous, ascending to appressed, pilose, angled, the angles keeled, winged, ciliate; sessile spikelet broadly ovate, 4-6 (-6.5) mm long, apex acute, glumes subequal, first glume glossy black, rounded, usually appressed hirsute, nerves 9-11, the nerves prominent at apex, second glume narrower, slightly keeled, 3-nerved at apex, first floret sterile, the lemma 3.8-5 mm long, hyaline, faintly nerved, margins ciliate, apex acute, second floret perfect, the lemma 3.9-4.3 mm long, hyaline, apex bifid, fimbriate, bearing a geniculate awn 5-8.5 (-11) mm long, terminal segment of awn short, 2-4 mm long, twisted in lower part, the palea 2.5-3 mm long, hyaline, nerveless, long-ciliate; pedicellate spikelets usually sterile, rarely staminate, narrowly lanceolate, 3.8-5 (-6) mm long, pedicel 0.7-2 mm long, with hairs 0.5-0.7 mm long, glumes subequal, first glume 9-11-nerved, flat to sulcate on back, clasping second glume, the second glume narrow, 3-nerved, appressed hirsute near the margins, lemma and palea 5-6 mm long, hyaline, faintly nerved, margins longciliate.  Caryopsis reddish brown to dark brown, spreading the glumes apart at maturity, broadly ovoid to globose, ca. 4 mm long, ca. 3.5 mm wide, somewhat dorsiventrally compressed, styles persistent" (Wagner et al., 1999; p. 1594).

Description from GrassBase.

Habitat/ecology:  "Occasionally cultivated, sparingly naturalized in Guam" (Stone, 1970; p. 239).  In Hawai‘i, "cultivated and sparingly naturalized along roadsides and in abandoned fields, 20-110 m" (Wagner et al., 1999; p. 1594).

Propagation:  Seed

Native range:  Northern Africa.

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		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1990) (voucher ID: PTBG 9110) Taxon name on voucher: Sorghum sudanense
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60) Varieties cafer Fosb. & Sachet and rotundulum (Snowden) Fosb. & Sachet
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced invasive cultivated	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Voucher cited: Evans 2223 (US); var. rotundulum (Snowden) Fosberg & Sachet; voucher cited: Hosaka 3049 (US, BISH) Persisting from cultivation.
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60) Varieties cafer Fosb. & Sachet and subglobosum (Hack.) Snowden
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Voucher cited: Herbst & Falanruw 6807 (US); var. subglobosum (Hack.) Snowden; voucher cited: Fosberg 24939 (US, BISH) Persisting from cultivation
Cook Islands Southern Cook Islands	Aitutaki Atoll		McCormack, Gerald (2011)
Cook Islands Southern Cook Islands	‘Atiu Island		McCormack, Gerald (2011)
Cook Islands Southern Cook Islands	Mangaia Island		McCormack, Gerald (2011)
Cook Islands Southern Cook Islands	Ma‘uke Island		McCormack, Gerald (2011)
Cook Islands Southern Cook Islands	Miti‘aro Island		McCormack, Gerald (2011)
Cook Islands Southern Cook Islands	Rarotonga Island		McCormack, Gerald (2011)
Federated States of Micronesia Chuuk Islands	Weno (Moen) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Federated States of Micronesia Chuuk Islands	Weno (Moen) Island	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Var. rotundulum (Snowden) Fosberg & Sachet; voucher cited: ar. rotundulum (Snowden) Fosberg & Sachet; voucher cited: Fosberg & Pelzer 26020 (US, BISH, MO, BRI, L) Persisting from cultivation
Federated States of Micronesia Yap Islands	Ulithi Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Federated States of Micronesia Yap Islands	Woleai Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Federated States of Micronesia Yap Islands	Woleai Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Var. rotundulum (Snowden) Fosberg & Sachet; voucher cited: ar. rotundulum (Snowden) Fosberg & Sachet; voucher cited: Wong 7 (US) Persisting from cultivation
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) var. rotundulum (Snowden) Fosberg & Sachet; voucher cited: ar. rotundulum (Snowden) Fosberg & Sachet; voucher cited: ar. rotundulum (Snowden) Fosberg & Sachet; voucher cited: Wong 520 (US) Persisting from cultivation
Fiji Fiji Islands	Viti Levu Island	introduced invasive cultivated	Smith, Albert C. (1979) (p. 376)
French Polynesia Gambier Islands	Mangareva (Gambier) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) As Sorghum sudanense (C.V. Piper) O. Stapf. Adventice
French Polynesia Marquesas Islands	Hiva Oa Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) As Sorghum sudanense (C.V. Piper) O. Stapf. Adventice
French Polynesia Society Islands	Moorea Island		Welsh, S. L. (1998)
French Polynesia Society Islands	Raiatea (Havai) Island	introduced invasive	Welsh, S. L. (1998) (p. 345) Voucher cited: Moore 732
French Polynesia Society Islands	Raiatea (Havai) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) As Sorghum cf. sudanense. Voucher cited: J. Florence 3509 (PAP) Adventice
French Polynesia Society Islands	Taha‘a Island	introduced	Fosberg, F. R. (1997) (p. 106)
French Polynesia Society Islands	Taha‘a Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) As Sorghum sudanense (C.V. Piper) O. Stapf. Voucher cited: J. Florence 10606 (PAP) Adventice
French Polynesia Society Islands	Tahiti Island	introduced invasive	Welsh, S. L. (1998) (p. 345) Voucher cited: Florence 2810
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) As Sorghum sudanense (C.V. Piper) O. Stapf. Adventice
French Polynesia Austral (Tubuai) Islands	Rimatara (Rimitara) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) As Sorghum sudanense (C.V. Piper) O. Stapf. Adventice
Guam Guam Island	Guam Island	introduced invasive cultivated	Stone, Benjamin C. (1970) (p. 239) Sparingly naturalized.
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60) Varieties cafer Fosb. & Sachet and subglabrescens (Steud.) Fosb. & Sachet
Guam Guam Island	Guam Island	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Vouchers cited: Sachet 1715 (US, BISH), McGregor 513 (US); var. subglabrescens (Steud.) Fosberg & Sachet; voucher cited: Stone 4753 (GUAM)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1594)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1594)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2003) (p. 22) West Maui. Voucher cited: Oppenheimer H110004 (BISH, PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 39) East Maui. Vouchers cited: Starr & Starr 040501-1 (BISH), Starr, Starr & Fukada 040505-2 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1594) Voucher cited: Mann & Brigham 389 (BISH)
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands	introduced	Kato, Hidetoshi (2007)
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Var. obbovatum (Hack.) Fosberg & Sachet; vouchers cited: Fosberg 24383 (US,BISH, POM, MO, K, CANB, NY, L), Taylor 46-1305 (US)
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced cultivated	St. John, Harold (1960) (p. 323) Voucher cited: Taylor 46-1305
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced invasive	Fosberg, F. R. (1955) (p. 4) Var. obbovatum; voucher cited: Fosberg 24383 (US)
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Var. rotundulum (Snowden) Fosberg & Sachet; voucher cited: Fosberg 26705 (US, BISH, K, CANB, POM, MO) Persisting from cultivation
Marshall Islands Ralik Chain	Jaluit (Jãlwõj) Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1962) (p. 6) Vouchers cited: St. John (BISH), Fosberg 26705 (US)
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced	Vander Velde, Nancy (2003) (p. 53) Rare and probably extirpated.
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced invasive	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 93-96) Var. rotundulum (Snowden) Fosberg & Sachet; voucher cited: Fosberg 26932 (US, BISH, POM, BRI, L) Persisting from cultivation
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive cultivated	MacKee, H. S. (1994) (p. 62) Voucher cited: MacKee 23721 Spontané
Niue Niue	Niue Island	introduced invasive	Sykes, W. R. (1970) (p. 251) Incorrect as Sorghum halepense per Sykes, pers. com. Vouchers cited: CHR 168734, CHR 168735, CHR 168754
Niue Niue	Niue Island	introduced invasive cultivated	Yuncker, T. G. (1943) (p. 24) Incorrect as Sorghum halepense per Sykes, pers. com. Voucher cited: Yuncker 9723 (BISH). Also as Sorghum vulgare Pers., voucher cited: Yuncker 9878. "Occasional in waste areas and on rocky cliffs near the sea".
Palau Palau (main island group)	Malakal Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60)
Philippines Philippine Islands	Philippine Islands	introduced cultivated	Merrill, Elmer D. (1925) (p. 48) As Andropogon sorghum (Linn.) Brot. Cultivated but not established.
Philippines Philippine Islands	Philippine Islands		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 135)
Pitcairn Islands Pitcairn Islands	Pitcairn Island	introduced	St. John, H. (1987) (p. 24) Sorghum sudanense (Piper) Stapf in rain; vouchers cited: Ross 42, R. A. Young 10, Fosberg & B. Christian 11224
Pitcairn Islands Pitcairn Islands	Pitcairn Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) As Sorghum sudanense (C.V. Piper) O. Stapf. Adventice
Tonga Tongatapu Group	Tongatapu Island		Sykes, Bill (year unknown) ?
Tonga Vava‘u Group	Late Island	introduced	Sykes, W. R. (1981) (p. 352)
United States (other Pacific offshore islands) Wake Islands	Wake Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 59-60) ?
Wallis and Futuna Wallis and Futuna (Horne) Islands	Wallis (‘Uvea) Island	introduced invasive	Meyer, Jean-Yves (2007) (p. 12) As Sorghum sudanense (=Sorghum bicolor ssp. drommondii). Cette grande herbacée est localement naturalisée en bordure de routes et de pistes, et de zones cultivées.
Wallis and Futuna Wallis and Futuna (Horne) Islands	Wallis and Futuna Islands		Swarbrick, John T. (1997)

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. 135)
China China	China (People's Republic of)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 135)
China China	Hong Kong	introduced cultivated	Wu, Te-lin (2001) (p. 348) Also as Sorghum sudanense (Piper) Stapf [= Sorghum bicolor nothosubsp. drummondii]
Indonesia Indonesia	Indonesia (Republic of)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 135)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 192)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 610) "Cultivated ground, crops (often asparagus or maize), roadsides, railway lines".

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	introduced invasive	Swarbrick, J. T. (1997) (p. 128)
Australia (Indian Ocean offshore islands) Cocos (Keeling) Islands	Cocos (Keeling) Islands	introduced invasive	Orchard, Anthony E., ed. (1993) (p. 38)
Maldives Maldive Islands	Maldive Islands		Fosberg, F. R. (1957) (p. 12)

Comments:  A similar species, Sorghum arundinaceum (Desv.) Stapf., was found on Niue (at the end of the airport runway and other locations) (Space & Flynn, 2000).

Includes var. cafer (Koern.) Fosb. & Sachet, var. obovatum (Hack.) Fosb. & Sachet, var. rotundulum (Snowden) Fosb. & Sachet, var. subglabrescens (Steud.) Fosb. & Sachet, var. subglobosum (Hack.), var. technicum (Koern.) Stapf ex Holland and var. transiens (Hack.) Fosb. & Sachet.

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

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

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

References:

Binggeli, P./Starmer, J. 1997. Pitcairn Island. Aliens 6:2.

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. 1955. Northern Marshall Islands Expedition, 1951-1952. Land biota: vascular plants. Atoll Research Bulletin No. 39. Pacific Science Board, National Academy of Sciences, Washington. 22 pp.

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. 1997. Preliminary checklist of the flowering plants and ferns of the Society Islands. Ed. by David R. Stoddart. U. Cal. Berkeley.

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.

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

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.

McCormack, Gerald. 2011. Cook Islands Biodiversity Database, Version 2007.2. Cook Islands Natural Heritage Trust, Rarotonga.

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

Meyer, Jean-Yves. 2007. Rapport de mission sur l'Ile d'Uvea (Wallis & Futuna) du 6 au 17 Novembre 2007: Inventaire preliminaire de la flore vasculaire secondaire [unpublished report]. Délégation à la Recherche, Ministère de l'Education, l'Enseignement Supérieur et la Recherche, B.P. 20981 Papeete, Tahiti, Polynésie française. 39 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.

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.

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./Flynn, Tim. 2000. Report to the Government of Niue on invasive plant species of environmental concern.  USDA Forest Service, Honolulu. 34 pp.

St. John, H. 1987. An account of the flora of Pitcairn Island with new Pandanus species. Pacific Plant Studies 46. Honolulu, 65 pp. [Privately published].

St. John, Harold. 1960. Flora of Eniwetok Atoll. Pacific Science 14(4):313-336.

Starr, Forest/Starr, Kim/Loope, Lloyd L. 2006. New plant records from the Hawaiian Archipelago. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 1: Articles. Bishop Museum Occasional Papers 87:31-43.

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.

Sykes, Bill. 0. Bill Sykes, pers. com.

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

Sykes, W. R. 1981. The vegetation of Late, Tonga. Allertonia 2(6):323-353.

U.S. Dept. Agr., Agr. Res. Serv. 2011. 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.

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).

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.

Whistler, W. A. 1988. Checklist of the weed flora of western Polynesia. Technical Paper No. 194, South Pacific Commission, Noumea, New Caledonia. 69 pp.

Whistler, W. A./Atherton, J. 1997. Botanical survey of the Huvalu Forest Conservation Area, Niue. Unpublished technical report. 76 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.

Yuncker, T. G. 1943. The flora of Niue Island. Bishop Mus. Bull. 178. Bishop Museum Press, Honolulu. 126 pp.

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