Pacific Island Ecosystems at Risk (PIER)

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Digitaria bicornis
(Lam.) Roem. & Schult., Poaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Digitaria commutata Schult.; Paspalum bicorne Lam.

Common name(s): [more details]

Chinese: yi ma tang

English: Asian crab grass, crab grass, large crab grass, southern crabgrass

Habit:  grass

Description:  "Annual, at first tufted, culms later decumbent, rooting at the nodes, forming loose mats; flowering culms ascendingly erect, up to 60 cm high.  Cataphylls absent.  Sheaths moderately pilose to glabrous.  Ligule 1-3.5 mm high, truncate, erose.  Blades linear, 2.5-13.5 (-23) cm by 2-9 mm, patent to ascending, soft, usually scabrous on both sides, glabrous but for some in the throat, rarely sparsely pilose.  Peduncle up to 40 cm long, glabrous.  Racemes 2-5 (-10), longest 3.5-14.5 cm long, digitate or in up to 3 whorls along an up to 5 cm long common axis.  Rachis winged, serrate, spicules at least 0.05 mm long, rarely with some setae at base ('rachiseta').  Abscission of pedicels truncate, Spikelets binate, usually heteromorph, the sessile one glabrous to slightly pubescent, the pedicelled one pubescent, to both pectinate and pubescent, lanceolate, 2.75-3.5 mm long; hairs smooth, acute.  Lower glume very variable, 0.15-0.4 (-0.75) mm long, from nearly absent to a triangular scale, acute to bifid.  Upper glume 1-2.75 mm long, 0.35-0.8 times as long as the spikelet, nerves 3, pubescent, hairs overtopping.  Sterile lemma as long as the spikelet, that of the sessile spikelet usually glabrous and equidistantly 7-nerved, to slightly pubescent and inequidistantly nerved (the pedicelled spikelet then always pectinate!), to pubescent and pectinate (spikelets then homomorphous), those of the pedicelled spikelet usually pubescent and inequidistantly nerved, pubescence usually mixed with bristles, these indistinct and appressed in youth, patent and protruding from the pubescence in fruit, rarely and then only the basal spikelets homomorphous, glabrous and equidistantly nerved (the whole raceme should therefore be inspected!); nerves usually smooth, the second nerves sometimes minutely serrulate towards the apex.  Fertile lemma slightly shorter than the spikelet, yellowish in fruit.  Anthers 0.5-0.6 mm long, purple.  Stigma purple"  (Veldkamp, 1973; pp. 30-32).

"Small grass with awnless spikelets in digitately arranged panicle branches" (Whistler, 1988; p. 50).

Description from GrassBase.

Habitat/ecology:  "In American Samoa and Samoa, "uncommon in disturbed places" (Whistler, 1988; p. 50).  "Waste places, often on sand, also along the shore and in the dunes, up to 2000 m in New Guinea, but to 2450 m in Assam." (Veldkamp, 1973; pp. 30-32)

Propagation:  Seed

Native range:  Eastern and southeastern Asia, Australia; naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
American Samoa
Tutuila Islands
Tutuila Island   Whistler, W. A. (1988) (p. 50)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Agrigan (Agrihan) Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Voucher cited: Fosberg 31606 (US, BISH, POM, NY, L)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Guguan Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Guguan Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Voucher cited: Falanruw 1801 (US)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Pagan Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Pagan Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Voucher cited: Fosberg 31366 (US, BISH, POM)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Rota Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Tinian Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Tinian Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Vouchers cited: Hosaka 2836 (US, BISH, POM), Fosberg 24813 (US, BISH, POM)
Federated States of Micronesia
Pohnpei Islands
Pohnpei Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
?
Federated States of Micronesia
Pohnpei Islands
Pohnpei Island introduced
invasive
Herrera, Katherine/Lorence, David H./Flynn, Timothy/Balick, Michael J. (2010) (p. 56)
Naturalized
Federated States of Micronesia
Pohnpei Islands
Pohnpei Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Voucher cited: Hatusima 10922 (FU)
Federated States of Micronesia
Yap Islands
Yap (Waqab) Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Federated States of Micronesia
Yap Islands
Yap (Waqab) Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Voucher cited: Hosaka 3297 (US, BISH, POM, NY)
Guam
Guam Island
Guam Island introduced
Raulerson, L. (2006) (p. 8)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Snow, Neil/Lau, Alex (2010) (p. 50)
West Maui. Voucher cited: H. Oppenheimer H20816 (BISH)
Nauru
Nauru Island
Nauru Island introduced
invasive
Thaman, R. R./Fosberg, F. R./Manner, H. I./Hassall, D. C. (1994) (p. 69)
Voucher cited: Scully 152N (US?)
New Guinea (Indonesia and Papua New Guinea)
New Guinea Island
New Guinea Island native
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Palau
Palau (Belau ) (main island group)
Babeldaob Island   Raulerson, L./Rinehart, A. F./Falanruw, M. C. (1996) (p. 21)
Palau
Palau (Belau ) (main island group)
Ngerkebesang Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Palau
Palau (Belau ) (main island group)
Ngerkebesang Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Voucher cited: Takamatsu 1867a (BISH)
Philippines
Philippine Islands
Philippine Islands native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Samoa
Western Samoa Islands
Upolu Island   Whistler, W. A. (1988) (p. 50)
United States (other Pacific offshore islands)
Wake Islands
Wake Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
United States (other Pacific offshore islands)
Wake Islands
Wake Island introduced
Fosberg, F. R./Falanruw, M. V. C. (1980) (pp. 201-202)
Vouchers cited: Fosberg 34936 (US), Brankamp in 1936 (BISH), Lyons 10 (BISH)
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) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Western Australia
Australia
Australia (continental)
Northern Territory native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Australia
Australia (continental)
Queensland native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Cambodia
Cambodia
Cambodia (Kingdom of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
China (People's Republic of) native
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Waste ground, often on sand, including seashore sand; below 2000 m. Fujian, Hainan, Yunnan.
Colombia
Colombia
Colombia (Republic of) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Ecuador (Mainland)
Ecuador
Ecuador (Republic of) (continental) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
El Salvador
El Salvador
El Salvador (Republic of) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Guatemala
Guatemala
Guatemala (Republic of) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Honduras
Honduras
Honduras (Republic of) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Indonesia
Indonesia
Indonesia (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Malaysia
Malaysia
Malaysia (country of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico
Mexico
Mexico (United Mexican States) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Nicaragua
Nicaragua
Nicaragua (Republic of) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Panama
Panama
Panama (Republic of) introduced
invasive
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
Singapore
Singapore
Singapore (Republic of) native
Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 34)
Common
Thailand
Thailand
Thailand (Kingdom of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam
Vietnam
Vietnam (Socialist Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Seychelles
Seychelles Islands
Agalega Island native
Fosberg, F. R./Sachet, Marie-Hélène/Stoddart, D. R. (1983) (p. 132)
Also reported from
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
United States (continental except west coast)
United States (other states)
United States (other states) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (continental except west coast)
United States (other states)
USA (Florida) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Comments:  GRIN and the Flora of China online say it is naturalized in the United States while the PLANTS database says it is native.


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This page was created on 1 SEP 2002 and was last updated on 14 APR 2013.