Leersia hexandra Sw., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Homalocenchrus hexandrus (Sw.) Kuntze

Common name(s): [more details]

Chinese: li shi he

English: clubhead cutgrass, cutgrass, southern cutgrass, swamp rice grass

Filipino: barit

Spanish: arrocillo, arroz bravo, hierba de arroz, pasto de agua

Habit:  grass

Description:  "A perennial grass; culms hollow, usually creeping and rooting at the base, the upper part erect, slender, with fine longitudinal lines, 30 to 120 cm tall; leaf sheath with thickened, fleshy, cuff-like base (sheath-node) which is densely covered with white-rough hairs bent or turned over backward; ligule 4 to 9 mm, smooth, sometimes thin and rather stiff and dry (scarious); blades tapering at base, acute, rough on both sides, rolled at night or when dry, 15 to 30 cm long, 4 to 6 mm wide; panicles erect or nodding, 5 to 12 cm, spreading or contracted, the branches slender, naked at base; spikelets in two series, overlapping, with a small knoblike projection (callus) at the base of the spikelet, 2.5 to 4.5 mm; outer bracts white or purple between green nerves, five-nerved, the mid-nerves comb-like, the inner bract much narrower, acute, three-nerved; fruit (caryopsis) oblong, but seldom produced.  The hollow slender culms with fine longitudinal lines and the outer bracts of the spikelets with comb-like (pectinate) projections extending from the mid-nerves are distinguishing characteristics of this species"  (Holm et al., 1977; p. 303).

"Perennial; culms 30 cm to 1 m high, slender, often decumbent, ascending from a creeping rhizome, silky pubescent at the nodes.  Leaf-blades mostly 10-20 cm long and 4-8 mm broad, flat, painfully retrorsely scabrid on the midrib beneath; ligule 1-2 mm long, asymmetric, truncate or obliquely truncate.  Panicle narrowly elliptic to oblong, 5-12 cm long and 1-4 cm wide; branches ascending, bearing spikelets almost to the base. Spikelets oblong, (3.2-) 3.4-4.8 (-5.2) mm long and (1-) 1.2-1.4 (-1.7) mm broad, pale or purplish; lemma conspicuously pectinate-ciliate, or rarely spinulose, on the keel" (Clayton, 1970; pp. 25, 27).

Description from GrassBase.

Habitat/ecology:  "It is a salt-shy grass found on permanent moist or marshy habitats, along irrigation ditches and other watersides, in humid thickets, in ponds, in rice fields, and on moist arable lands.  The species can extend into temperate climates whether by reason of latitude or the presence of high valleys or tablelands in the tropics, and it ha, therefore, a most interesting distribution and adaptation"  (Holm et al., 1977; p. 303).

In east Africa, "in shallow water, often forming extensive matted carpets on flood plains and in swamps, up to 2000 m" (Clayton, 1970; pp. 25, 27).

Propagation:  "The plant reproduces by seeds but is easily propagated by division of rhizomes.  The culms are often creeping and, if they are cut into pieces and spread on wet soil, they root at every node" (Holm et al., 1977; p. 303).

Native range:  Tropical America (Holm et al., 1977; p. 303). Pantropic in wetlands (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Foundation (2008)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Henty, E. E. (1969) (p. 117) In wet situations from near sea level to 7000 ft., usually gregarious, on marshy land, or in the shallow water of lake-edges. It is often a major constituent of the floating islands which are a feature of several New Guinea lakes and rivers.
Philippines Philippine Islands	Philippine Islands	introduced invasive	Waterhouse, D. F. (1993) (pp. 66, 77)
Philippines Philippine Islands	Philippine Islands	cultivated	Merrill, Elmer D. (1925) (p. 78) In open wet places at low and medium altitudes, ascending to 1,500 m. Cultivated in paddies for green forage.

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)	New South Wales	native	National Herbarium of New South Wales (2013) "Usually grows in and around swamps and creeks."
Australia Australia (continental)	Northern Territory	native	National Herbarium of New South Wales (2013)
Australia Australia (continental)	Queensland	native	National Herbarium of New South Wales (2013)
Cambodia Cambodia	Cambodia (Kingdom of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 66, 77)
China China	China (People's Republic of)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 92)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 339) Along streams, in marshes.
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 66, 77)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 66, 77)
Mexico Mexico	Mexico (United Mexican States)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 92)
Negara Brunei Darussalam Brunei	Brunei (Negara Brunei Darussalam)	introduced invasive	Waterhouse, D. F. (1993) (pp. 66, 77)
Singapore Singapore	Singapore (Republic of)	introduced invasive	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. 53) Weed of uncertain origin
Thailand Thailand	Thailand (Kingdom of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 66, 77)
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 66, 77)

Comments:  A valuable fodder grass, but also a weed of numerous crops (Holm et al., 1977; p. 609).

Control:  If you know of control methods for Leersia hexandra, please let us know.