Ischaemum rugosum Salisbury, Poaceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: tian jian ya zui cao

English: murain grass, muraina grass, muraino grass, ribbed muraina grass, saramatta grass, wrinkle duck-beak, wrinkled grass

Fijian: co muraina, tho muraina

Pangasinan: gulonglapas

Spanish: capim macho, mazorquilla, pela bolsillo, trigillo

Subanen: daua, dauna

Tagalog: tinitrígo, tinitrigo

Habit:  grass

Description:  "An annual grass; culms 60 to 120 cm high, branched and purplish, erect or ascending; sheaths fairly loose, and pilose on margins near tips, densely soft-hairy on the nodes; ligule 1 to 7 mm, fused with the auricles; blades linear-lanceolate, sparingly pilose on both surfaces, 20 to 30 cm long and 9 to 12 mm wide; inflorescence in paired racemes 5 to 10  cm long, firmly adpressed together at the base but gradually separating, with one flat side each; spikelets 3 to 4.5 mm long, lower spikelet sessile, upper spikelet stalked, obtuse, awned; lower glume of sessile spikelet strongly transversely ribbed, hard, with a green, herbaceous, ovate tip, about 6 mm long, yellowish, keels unequally winged above, one keel of lower glume of stalked spikelet with a wide crescent shaped wing; awn 1.8 to 2.5 cm long, slender, spirally twisted in the lower half; seed 2.5 to 3 mm long, 1 mm wide, triangular in cross section, oblong, small tip (mucro), slightly concave near point of attachment.  The species is easily recognized when in flower by the prominent transverse ribs or ridges on the lower glume of the spikelet.  These are distinctive and can be seen with the naked eye.  Also, the prominent spinal awns and the tufted hairy nodes of the culm are excellent diagnostic characters for this weed" (Holm et al., 1977; p. 295).

"Annual [grass]; culms 60-120 cm high, branched, purplish, with bearded nodes; sheaths fairly loose, pilose at apical margins; blades up to 30 cm long and up to 12 mm wide; racemes paired, 4-10 cm long, at first pressed together, later separating; lower glume of sessile spikelet strongly transversely ribbed, hard, with a green ovate tip, yellowish; awn up to 2.5 cm long, slender, spirally twisted in the lower half" (Stone, 1970; p. 234).

Description from GrassBase.

Habitat/ecology:  "A weed of low country, swamps, and paddy fields.  In the Philippines it is found in wet grasslands at sea level but also grows up to 2,400 m. It is mainly a problem in warm humid regions often near the equator" (Holm et al., 1977; p. 295).  Most common in low country wet areas, but can grow from sea level to 2400 m. In Fiji, "found along roadsides and in swamps as well as in rice fields" (Smith, 1979; p. 372).

Propagation:  Seed.  "In the Philippines it has been shown that some plants may produce 4,000 seeds.  It flowers and fruits in February and October in Fiji.  The seeds have a dormant period after they have matured" (Holm et al., 1977; p. 295).

Native range:  Southern, eastern and southeastern Asia to the Philippines; northern Australia (GRIN). Possibly native to Guam, although equally probably an introduced species, according to Stone (1970; p. 234).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Fiji Fiji Islands	Vanua Levu Island	introduced invasive	Smith, Albert C. (1979) (p. 372) Vouchers cited: DA 8789, DA 16876
Fiji Fiji Islands	Vanua Levu Island		Bishop Museum (Honolulu) (1969) (voucher ID: BISH 31707) Taxon name on voucher: Ischaemum rugosum Salisb.
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1979) (p. 372) Vouchers cited: DA 8226, DA 9135, DA 2804, DA 10110, DA 2900, DA 7814, DA 7877, DA 7925, DA 9917, DA 9380, DA 3973, DA 3673, C.R. Turbet 24, DA 9126
Fiji Fiji Islands	Viti Levu Island		Bishop Museum (Honolulu) (1955) (voucher ID: BISH 31706) Taxon name on voucher: Ischaemum rugosum Salisb.
Guam Guam Island	Guam Island	uncertain if native invasive	Stone, Benjamin C. (1970) (p. 234) Voucher cited: G.E.S. 213
Guam Guam Island	Guam Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 47) Var. segetum (Trin.) Hackel per Fosberg et al. (1987).
Guam Guam Island	Guam Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 95)
Guam Guam Island	Guam Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 68-69) Var. segetum (Trin.) Hack.; vouchers cited: G.E.S. 213 (US), Nelson 212 (BISH)
Guam Guam Island	Guam Island		Bishop Museum (Honolulu) (year unknown) (voucher ID: BISH 125173) Taxon name on voucher: Ischaemum rugosum Salisb.
Guam Guam Island	Guam Island		Bishop Museum (Honolulu) (1918) (voucher ID: BISH 125174) Taxon name on voucher: Ischaemum rugosum Salisb.
Palau Palau (Belau ) (main island group)	Babeldaob Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 47) Var. segetum (Trin.) Hackel per Fosberg et al. (1987).
Palau Palau (Belau ) (main island group)	Babeldaob Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 68-69) Var. segetum (Trin.) Hack.; voucher cited: Hatusima 5025 (FU)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands	native	Merrill, Elmer D. (1925) (pp. 38-39) In open usually rather wet grasslands.
Wallis and Futuna Wallis and Futuna (Horne) Islands	Wallis and Futuna Islands		Whistler, W. A. (1988) (p. 53)

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)	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)
Central America Central America (Pacific rim)	Costa Rica (Republic of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Marshy fields, ditch banks, river banks, other wet often slightly saline grassy places; 100-1800 m. Guangdong, Guangxi, Guizhou, Hainan, Sichuan, Yunnan.
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 339) In wet places.
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
Negara Brunei Darussalam Brunei	Brunei (Negara Brunei Darussalam)	native	Waterhouse, D. F. (1993) (pp. 66, 77)
Singapore Singapore	Singapore (Republic of)	native	Waterhouse, D. F. (1993) (pp. 66, 77)
Singapore Singapore	Singapore (Republic of)	uncertain if introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 51) Weed of uncertain origin
South America (Pacific rim) South America (Pacific rim)	Colombia	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 297)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 297)
Taiwan Taiwan Island	Taiwan Island	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Marshy fields, ditch banks, river banks, other wet often slightly saline grassy places; 100-1800 m.
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)

Comments:  A noxious weed in Fiji. On U.S. Federal noxious weed list.

Control:  If you know of control methods for Ischaemum rugosum, please let us know.