Eleocharis acicularis (L.) Roem. & Schult., Cyperaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: niu mao zhan, song mao lin, song ye lin

English: dwarf hair-grass, needle spike-rush, needle spikerush, needle spikesedge, slender spikerush

French: elééocharide aciculaire, héléocharis aciculaire, scirpe épingle

Japanese: matsubai

Spanish: hierba pilosa, junco de espiga, pasto de agua, pelillo, velita

Habit:  sedge

Description:  "A variable, tufted perennial sedge with small rhizomes that creep extensively, allowing the formation of mats or turf; rhizomes 0.3 to 0.6 mm thick; roots not fleshy; culms erect, slender, filiform, may be somewhat flattened, usually 4-angled with lengthwise grooves, smooth, 2 to 25 cm tall, 0.25 to 0.5 mm wide, in running water may be taller; leaf sheath thin, membranous, loose, summit may be subtruncate, reddish below, pallid or hyaline terminally; spikelets ovate to lanceolate, or may be linear, sometimes flattened, sessile, spirally arranged, usually 5 to 10 flowered but variable, about 3 to 3 mm long and 1 to 1.5 mm wide; glumes keeled or 1-nerved, oblong-ovate, midrib green, often with reddish or purplish sides, 1.5 to 2 mm long; bristles slender, up to 4, equaling or exceeding the length of the achene (nut), sometimes reduced or absent, stamens 2 or 3, anthers 0.5 to 1 mm long, style 3-parted; achene, obovate-oblong, obscurely trigonous or nearly round in cross section, up to 10 longitudinal ribs with valleys of horizontally elongate cells in a longitudinal series, 0.5 to 1 mm long, about 0.5 mm in diameter, weight 0.5 mg, apical tubercle minute, conic, skullcap-like, with bristles or lacking, color may be pearly white, yellow, pale gray or light brown"  (Holm et al., 1997; p. 310).

Habitat/ecology:  "Muddy river banks, vernal pools, lake shores and margins, marshes and shallow ponds and reservoirs, ditches, coastal lowlands and in deep or shallow water, depending on the season, stage of growth, wave action or competition.  Can infest the margins of open water bodies initially, then spread inward as conditions permit and finally contribute to the swamp-marsh-building process.  Grows very well in water of pH 2.8--a rare feat for spermatophytes.  Often troublesome in coastal grazing lands and wet areas of meadows and pastures"  (Holm et al., 1997; pp. 313, 315).

Propagation:  Seed and rooting fragments of plants. Locally by rhizomes and stolons (Holm et al., 1997; p. 317).

Native range:  Europe, Asia and the Americas; also cultivated (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 69)
Kiribati Tungaru (Gilbert) Islands	Onotoa Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 69)
Palau Palau (Belau ) (main island group)	Babeldaob Island	native	Raulerson, L./Rinehart, A. F./Falanruw, M. C. (1996) (p. 17)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Merrill, Elmer D. (1925) (p. 119) About rice paddies, altitude 1,200 to 1,500 m.
Solomon Islands Solomon Islands	Solomon Islands		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)

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		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
British Columbia (province of Canada) Province of British Columbia	Canada (British Columbia)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Cambodia Cambodia	Cambodia (Kingdom of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 311) In wet places.
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Celebes
Japan Japan	Japan		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
South Korea South Korea	South Korea (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
Malaysia Malaysia	Malaysia (country of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
Mexico Mexico	Mexico (United Mexican States)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Colombia		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan Taiwan Island	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Thailand Thailand	Thailand (Kingdom of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 314)
United States (west coast) United States (west coast states)	USA (Oregon)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Canada Canada	Canada	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast) United States (other states)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control:  If you know of control methods for Eleocharis acicularis, please let us know.