Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: luan cao

English: Japanese lovegrass, pond lovegrass

Habit:  grass

Description:  "Caespitose annuals. Culms 25-100 (115) cm tall, erect, sometimes geniculate below, branching from the lower and middle nodes, glabrous and somewhat shiny below the nodes.  Sheaths overlapping below, about 3/4 to 7/8 as long as the internodes above, glabrous at the summit and along the upper margins.  Ligules 0.4-0.6 mm long, a delicate membrane, glabrous.  Blades (4) 15-20 (25) cm long, 1.5-6 mm wide, flat, glabrous below and scaberulous above, sometimes auriculate near the base.  Panicle 15-40 cm long, 0.8-5 cm wide, condensed, lanceolate, interrupted below, the ascending, often appressed branches 2-10 cm long, spreading up to 30º from the culm axis, the branches scaberulous and shiny, floriferous near base; pulvini in the axils of the primary branches glabrous; pedicels 0.5-1.5 mm long, erect and sinuous.  Spikelets 2.2-3.8 mm long, 0.8-1.3 mm wide, 4-12-flowered, oblong to narrowly lanceolate, compressed, yellowish-brown to somewhat whitish and hyaline; disarticulation between the florets, the portion of the rachilla and floret falling as a unit.  Glumes 0.6-1 mm long, ovate to ovate-lanceolate, subequal, faintly keeled, scaberulous along the keel,, hyaline, 1-nerved or the first often without a nerve.  Lemmas 0.9-1.2 mm long, ovate, hyaline, the lateral nerves conspicuous below, greenish, keeled, glabrous along the keel, apex acute.  Paleas 0.6-0.8 mm long, bowed out, hyaline, scaberulous along the keel near the apex, apex acute, often bifid.  Stamens 2, anthers 0.1-0.2 mm long, whitish to light brown.  Caryopses 0.3-0.4 mm long, obovoid, smooth, reddish-brown" (Lægaard & Peterson, 2001; p. 39).

Description from GrassBase.

Habitat/ecology:  In Ecuador, "occurs in moist areas along rivers and streams, usually in sandy soils below 100 m" (Lægaard & Peterson, 2001; p. 39).

Propagation:  Seed

Native range:  "Native in tropical regions of Asia" (Lægaard & Peterson, 2001; p. 39. Widely naturalized in tropics and subtropics, native range obscure (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)		Henty, E. E. (1969) (p. 93) A weed of gardens, nursery beds, etc.
Philippines Philippine Islands	Philippine Islands		Waterhouse, D. F. (1993) (p. 65)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1925) (pp. 89-90) In open wet grasslands, along streams, etc., at low and medium altitudes.
Solomon Islands Solomon Islands	Solomon Islands	native	Hancock, I. R./Henderson, C. P. (1988) (p. 71)

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)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 145)
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 335) In farmland and other wet places.
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Japan	Japan (country)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Ryukyu Islands	Ryukyu Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Taiwan Taiwan	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Additional information:
Additional online information about Eragrostis japonica is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Eragrostis japonica as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Eragrostis japonica may be available from the Germplasm Resources Information Network (GRIN).

References:

Hancock, I. R./Henderson, C. P. 1988. Flora of the Solomon Islands. Research Bulletin No. 7. Ministry of Agriculture and Lands, Honiara. 203 pp.

Henty, E. E. 1969. A manual of the grasses of New Guinea. Department of Forests, Division of Botany, Botany Bull. No. 1. Lae, New Guinea. 215 pp.

Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. 1979. A geographical atlas of world weeds. John Wiley & Sons, New York. 391 pp.

Lægaard, Simon/Peterson, Paul M. 2001. 214 (2). Gramineae (part 2) Subfam. Chloridoideae. In: Harling, Gunnar and Lennart Anderson, eds. Flora of Ecuador 68.

Merrill, Elmer D. 1925. An enumeration of Philippine flowering plants, vol. 1 [reprint]. Bureau of Printing, Manila. 463 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Waterhouse, D. F. 1993. The major arthropod pests and weeds of agriculture in Southeast Asia. The Australian Centre for International Agricultural Research, Canberra. 141 pp.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).