Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: Jamaican crabgrass

French: gros meinki

Spanish: pata de gallina

Habit:  grass

Description:  "Erect grass with awnless spikelets in digitately arranged panicle branches bearing scattered hairs" (Whistler, 1988; p. 50).

"Annual with decumbent, spreading, branching, stoloniferous culm bases and erect floriferous shoots mostly 30-50 cm tall.  Sheaths hispid or pilose with long, spreading hairs.  Ligules 1.0-1.5 mm long. Blades thin, flat, mostly 5-15 mm broad, finely pilose on one or both surfaces.  Panicles with 5-15 slender, unbranched primary branches, at least the lower ones in verticils of 3-6.  Branch rachis usually with a few scattered, papilla-based hairs as much as 5-6 mm long.  Spikelets 2.0-2.5 mm long.  First glume usually absent, the second glume about half as long as spikelet, pilose on margins and tip.  Lemma of lower floret with 5 equidistant nerves, with a few soft hairs on the margins"  (Howard, 1979; pp. 106-107).

Description from GrassBase.

Habitat/ecology:  "A common weed of fields and waste places in the tropics of the world" (Wiggins & Porter, 1971; pp. 844-846). "A weed of disturbed, often sandy sites" (Howard, 1979; pp. 106-107).

In American Samoa and Samoa, "common to abundant in crops and sunny disturbed places" (Whistler, 1988; p. 50).

Propagation:  Seed

Native range:  Widespread in tropical regions of both hemispheres (Howard, 1979; pp. 106-107).

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	Ofu Island		Whistler, W. A. (1988) (p. 50) Voucher cited: Whistler 3448
American Samoa Tutuila Islands	Tutuila Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1992) (voucher ID: PTBG 16356) Taxon name on voucher: Digitaria horizontalis
Chile (offshore islands) Rapa Nui (Easter) Island	Rapa Nui (Easter) Island (Isla de Pasqua)	introduced	Skottsberg, Carl (1953) (p. 80)
Ecuador (Galápagos Islands) Española Group	Española Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Genovesa Group	Genovesa Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Sierra Negra, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Pinta Group	Pinta Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santiago Group	Rábida Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santiago Group	Santiago Island	introduced invasive	Charles Darwin Foundation (2008)
French Polynesia Marquesas Islands	Ua Pou (Huapu, Uapou, Uapu) Island	introduced abo. intro.	Lorence, David H./Wagner, Warren L. (2008) Voucher cited: D. H. Lorence, L. M. Dunn, J.-Y. Meyer 9334 (P, PAP, PTBG, US)
French Polynesia Society Islands	Tahiti Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1981) (voucher ID: PTBG 38248) Taxon name on voucher: Digitaria horizontalis Willd.
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1530, 1907)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1530)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Herbst, Derral R./Wagner, Warren L. (1999) (p. 26) Voucher cited: Herbst 696 (BISH) Forming extensive mats in abandoned pineapple fields.
Samoa Western Samoa Islands	Savai‘i Island		Whistler, W. A. (1988) (p. 50) Voucher cited: Whistler 28
Samoa Western Samoa Islands	Upolu Island		Whistler, W. A. (1988) (p. 50) Voucher cited: Whistler 2151
Tonga Tongatapu Group	Tongatapu Island		Yuncker, T. G. (1959) (p. 56) Voucher cited: Hürlimann 16

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (continental) Chile	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Colombia Colombia	Colombia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
El Salvador El Salvador	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Guatemala Guatemala	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Panama Panama	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island		Stoddart, D. R./Taylor, J. D., eds. (1971) (p. 145) Vouchers cited: Stoddart 797 (K), Soddart 846 (K, US)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island	introduced invasive	Whistler, W. Arthur (1996) (p. 24)
Maldives Maldive Islands	Addu Atoll		Spicer, R. A./Newberry, D. MacC. (1979) (p. 14)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 127)
Seychelles Seychelles Islands	Cousin Island	native	Fosberg, F. R. (1983) (p. 20) Voucher cited: Fosberg 52066 (US)
Seychelles Seychelles Islands	D'Arros Island		Stoddart, D. R./Coe, M. J./Fosberg, F. R. (1979) (p. 19) Vouchers cited: Gwynne & Wood 946 (EA), Gwynne & Wood 1025 (EA)
Seychelles Seychelles Islands	Frégate Island		Robertson, S. A./Todd, D. M. (1983) (p. 57) Voucher cited: Robertson 2685
Seychelles Seychelles Islands	Poivre Island		Robertson, S. A./Fosberg, F. R. (1983) (p. 172) Voucher cited: Robertson 2371 (K)

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

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

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

References:

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.

Fosberg, F. R. 1983. Natural history of Cousin Island. 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.

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

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.

Howard, Richard A. 1979. Flora of the Lesser Antilles: Leeward and Windward Islands. Vol. 3, Monocotyledoneae. Arnold Arboretum, Harvard University. 586 pp.

Lorence, David H./Wagner, Warren L. 2008. Flora of the Marquesas Islands. National Tropical Botanical Garden and the Smithsonian Institution. Online database.

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

National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.). 1981. Voucher specimen #PTBG38248(Art Whistler W 4834).

Robertson, S. A./Fosberg, F. R. 1983. List of plants of Poivre Island, Seychelles. 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.

Robertson, S. A./Todd, D. M. 1983. Vegetation of Frégate Island, Seychelles. 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.

Skottsberg, Carl. 1953. The natural history of Juan Fernandez and Easter Island. Vol. II, Botany. Almqvist &l; Wiksells, Uppsala. 960 pp.

Spicer, R. A./Newberry, D. MacC. 1979. The terrestrial vegetation of an Indian Ocean coral islands: Wilingili, Addu Atoll, Maldive Islands. I. Transect analysis of the vegetation. II. A limited quantitative analysis of the vegetation distribution. Atoll Research Bulletin 231. The Smithsonian Institution, Washington, D. C. 25 pp.

Stoddart, D. R./Coe, M. J./Fosberg, F. R. 1979. D'Arros and St. Joseph, Amirante Islands. Atoll Research Bulletin No. 223. The Smithsonian Institution, Washington, D.C. 48 pp.

Stoddart, D. R./Taylor, J. D., eds. 1971. Geography and ecology of Diego Garcia Atoll, Chagos Archipelago. Atoll Research Bulletin No. 149. Smithsonian Institution, Washington. 237 pp.

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.

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).

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

Wiggins, I. L./Porter, D. M. 1971. Flora of the Galapágos Islands. Stanford University Press. 998 pp.

Yuncker, T. G. 1959. Plants of Tonga. Bishop Museum Bull. 220. Bishop Museum Press, Honolulu. 343 pp.