Pacific Island Ecosystems at Risk (PIER)

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Panicum repens
L., Poaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  More information needed; score: 9 (Go to the risk assessment)

Common name(s): [more details]

Chinese: pu di shu

English: couch panicum, creeping panic, quack grass, torpedo grass, Victoria grass, wainaku grass

French: millet rampant, panic rampant

Manobo: kayana

Spanish: canota, grama del norte

Tagalog: luya-luyahan

Habit:  grass

Description:  "An erect, rather wiry, creeping, perennial grass, 30-90 cm tall, growing extensively but not densely, rhizomes strongly developed, often swollen or knotty, smooth with brownish or whitish scales, branched, sending out erect culms from the rather distant nodes; culms clothed at base with bladeless sheaths; leaf sheaths fringed with long hairs along the margin, ligule short, fringed with hairs; blades two-ranked, 15 to 25 cm long, 1.5 cm wide or less, acuminate, linear, flat or folded, with a rounded base, smooth or somewhat rough, sparsely long-hairy above, smooth below, covered with a whitish bloom, somewhat rigid, with long white hairs behind ligule, midrib prominent and keeled; panicles exserted, 7 to 18 cm long, somewhat loose and open, erect or ascending, sometimes nodding, elongated, scattered, one to three at each node, branches stiffly ascending, distant, 2 to 19 cm long, smooth or slightly rough; spikelets two-flowered, pale green or pale yellow, often tinged with purple, oblong-ovate, acute or slightly acuminate, 2.2 to 3 mm long; first glume truncate, about one-fifth as long as the spikelet, second glume as long as spikelet, seven- to nine-nerved; first lemma as long as spikelet, five- to nine-nerved; first palea nearly as long as spikelet; anthers yellowish orange; second lemma shorter than spikelet; stigmas purple; caryopsis lanceolate, straw-colored.  The sharp-pointed rhizome which is coarse, swollen, and shaped like a ginger rhizome and the blades which are often covered with whitish waxy bloom are the distinguishing characteristics of this species" (Holm et al., 1977; p. 353).

Description from GrassBase.

Habitat/ecology:  "Primary a weed of moist, coastal, sandy soils, it can also grow on heavy upland soils and can tolerate drought.  It is found most frequently in sandy soils along seacoasts or in poorly drained heavy soils.  It cannot stand permanently flooded conditions, but can withstand occasional flooding and can encroach upon and invade ditches, drains, watercourses, fishponds, and floating mats of vegetation from banks and adjacent areas.  It is frequent in cultivated lands, grasslands, roadsides, and gardens.  It is usually found in low coastal areas and along rivers but it does spread to local inland areas to elevations of 1,500 to 2,000 m in the tropics.  It grows best in open sunny areas but can stand partial shade.  It is very drought-resistant, an the rhizomes may live through prolonged dry periods" (Holm et al., 1977; pp. 353, 356).  Grows up to elevations of 2,000 m in Indonesia.  Favors open sunny conditions, but can stand partial shade.  Rhizomes can stand prolong dry periods  (Waterhouse, 1994; pp. 172-177).  In Hawai‘i, "naturalized in usually moist, disturbed habitats, such as along ditches and roadsides in cane fields, 30-1,100 m"  (Wagner et al., 1999; pp. 1571, 1573); "infests coastal sites and mesic to high-rainfall environments; forms thick, dense stands that smother low plants"  (Motooka et al., 2003).

Propagation:  "The plant spreads mainly by course, extensively creeping rhizomes that may extend as far as 7 m from the parent plant. Seeds are produced in a few situations" (Holm et al., 1977; p. 353).

Native range:  Tropical and north Africa, Mediterranean; now widespread in the tropics.

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island native
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 52)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island   Bishop Museum (Honolulu) (1984) (voucher ID: BISH 573466)
Taxon name on voucher: Panicum repens L.
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1571, 1573)
State of Hawaii
Hawaiian Islands
Lāna‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1571, 1573)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Starr, Forest/Martz, Kim/Loope, Lloyd L. (2002) (p. 23)
East Maui. Voucher cited: Starr & Martz 980927-1 (BISH)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1571, 1573)
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island native
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 52)
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island introduced
invasive
Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 81)
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island native
Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. Field notes and voucher.)
Voucher: Lorence 9771 (PTBG, BNM, NY, US)
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island   Beleu National Museum (Republic of Palau. Koror.) (1977) (voucher ID: BNM 10007)
Taxon name on voucher: Panicum repens L.
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2008) (voucher ID: PTBG 49527)
Taxon name on voucher: Panicum repens L.
Palau
Palau (Belau ) (main island group)
Palau Islands (main island group)   Bishop Museum (Honolulu) (1977) (voucher ID: BISH 428554)
Taxon name on voucher: Panicum repens L.
Philippines
Philippine Islands
Philippine Islands native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines
Philippine Islands
Philippine Islands native
Merrill, Elmer D. (1925) (p. 67)
In open low lands, especially near the sea, but also inland locally and ascending to 1,500 m; common.
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   Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 355)
Cambodia
Cambodia
Cambodia (Kingdom of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
China (People's Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
Hong Kong native
Wu, Te-lin (2001) (p. 342)
In wet places.
Indonesia
Indonesia
Indonesia (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan
Japan
Japan (country) 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)   Hafliger, Ernst/Scholz, Hildemar (1980) (p. 86)
Negara Brunei Darussalam
Brunei
Brunei (Negara Brunei Darussalam) introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)
Singapore
Singapore
Singapore (Republic of) introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)
Singapore
Singapore
Singapore (Republic of) native
Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 66)
Common
Taiwan
Taiwan Island
Taiwan Island native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Thailand
Thailand
Thailand (Kingdom of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (California) introduced
U.S. Dept. Agr., Nat. Res. Cons. 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
Australia (Indian Ocean offshore islands)
Cocos (Keeling) Islands
Cocos (Keeling) Islands native
Orchard, Anthony E., ed. (1993) (p. 38)
Seychelles
Seychelles Islands
Seychelles Islands introduced
Weber, Ewald (2003) (p. 298)
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) introduced
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (continental except west coast)
United States (other states)
USA (Florida) introduced
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Comments:  Planting of this species is prohibited in Miami-Dade County, Florida (U.S.) (Miami-Dade County Dept. of Planning and Zoning, 2010).

Control: 

Physical: "Difficult because of extensive rhizomes beneath soil surface. Tillage only encourages its growth"  (Motooka et al., 2003).

Chemical:  "Sensitive to glyphosate and imazapyr but will require repeat treatments" (Motooka et al., 2003).

Biological:  Waterhouse (1994, pp. 175-177) lists natural enemies of the species.


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This page was created on 1 JAN 1999 and was last updated on 4 JUL 2012.