Polypogon viridis (Gouan) Breistr., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Agrostis semiverticillata (Forssk.) C. Chr.

Common name(s): [more details]

Chinese: tai lü bang tou cao

English: beardless rabbitsfoot grass, water bent

French: agrostide demi-verticillée

Habit:  grass

Description:  "Perennials; culms strongly decumbent at base and rooting at nodes, (1.5-) 3-6 (-8) dm long.  Sheaths smooth, broad; ligule 1.5-4 (-6) mm long, truncate, erose-ciliolate and somewhat lacerate; blades flat, relatively wide, (1.5-) 2.5-4 (-7) mm long, upper surface smooth or scabrous.  Inflorescences paniculate, (2-) 4-10 (-16) cm long, compact, interrupted, the branches ascending to erect, spikelet-bearing to base; spikelets slightly laterally compressed, rachilla not prolonged; glumes small, subequal, (1.2-) 1.5-1.8 (-2) mm long, 1-nerved, densely and evenly scabrous, first glume ovate, second glume lanceolate; lemma membranous, 0.8-1.2 mm long, awnless, minutely apiculate by the excurrent nerves, callus blunt and glabrous; palea 0.5-1 mm long.  Caryopsis brown, cylindrical, 0.7-1 mm long, ca. 0.3 mm wide"  (Wagner et al., 1999; p. 1494).

Description from GrassBase.

Habitat/ecology:  In Hawai‘i, "naturalized in moist places, especially along steams, irrigation ditches, and seepage areas, 160-1,220 m"  (Wagner et al., 1999; p. 1494).

Propagation:  Seed

Native range:  "Native range unknown, occurring throughout the Old World tropics and in the Americas from Texas to Argentina" (Wagner et al., 1999; p. 1494). Macaronesia, northern Africa, Europe, western and central Asia; naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1494)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1494) Vouchers cited: Knudsen s.n. (B), Mann & Brigham 273 (B)

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)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 124)
China China	China (People's Republic of)		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Aquatic grass rooting in sand and mud of streams, marshy grasslands; ca. 2600 m. Yunnan.
Mexico Mexico	Mexico (United Mexican States)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 124)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 289) "Lowland in waste ground, roadsides and edges of ditches, often in damp places, occasionally a garden weed".

Control:  If you know of control methods for Polypogon viridis, please let us know.