Present on Pacific Islands?  yes

Threat only at high elevations?  no

Common name(s): [more details]

English: Jamaican crabgrass

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 World Grass Species.

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
Ecuador (Galápagos Islands) Española Group	Española Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Genovesa Group	Genovesa Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcan Sierra Negra	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santiago Group	Rábida Island	introduced invasive	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santiago Group	Santiago Island	introduced invasive	Charles Darwin Research Station (2005)
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. (2007)
Colombia Colombia	Colombia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
El Salvador El Salvador	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Guatemala Guatemala	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Panama Panama	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)

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)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 127)

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

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

References:

Charles Darwin Research Station. 2005. CDRS Herbarium records.

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.

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. 2006. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2007. 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.

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.