Pacific Island Ecosystems at Risk (PIER)

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Polypogon interruptus
Kunth, Poaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: ditch beard grass, ditch polypogon, ditch rabbitsfoot grass

Habit:  grass

Description:  "Perennials; culms tufted, 0.5-6 (-9) dm tall, sometimes decumbent at base and rooting at nodes.  Sheaths smooth to scaberulous, margins overlapping, thin; ligule translucent, firm, (1.5-) 3-7 (-9.5) mm long, nerved, puberulent, margins entire to lacerate, apex narrowed, obtuse, or truncate; blades flat, 2-5 (-9) mm wide, scabrous.  Panicles 2-9 (-15) cm long, interrupted, branches erect; glumes subequal, 1.7-2.5 mm long, keeled, hispidulous, apex narrowed abruptly into a terminal awn, sometimes minutely bifid, the awn (1-) 1.5-3 (-5) mm long; lemma narrowly lanceolate, (0.7-) 1-1.5 mm long, smooth, glossy, apex minutely bifid, awned from near apex, the awn ca. 3 mm long; palea similar and nearly as long as lemma.  Caryopsis pale brown, narrowly ovoid, 0.6-0.8 mm long"  (Wagner et al., 1999; p. 1585-1586).

Description and other information from World Grass Species database.

Habitat/ecology:  In Hawai‘i, "naturalized and common in wet sites such as along streams, roadside drainages, in wet forest, and near rock seeps, 0-1,980 m"  (Wagner et al., 1999; p. 1585).

Propagation:  Seed

Native range:  Western and southern South America, 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. 1586)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1586)
State of Hawaii
Hawaiian Islands
Kure Atoll introduced
invasive
Wagner, Warren L./Herbst, Derral R. (1995) (p. 24)
Voucher cited: Saito s.n. (BISH)
State of Hawaii
Hawaiian Islands
Kure Atoll introduced
invasive
Starr, Forest/Martz, Kim/Loope, Lloyd (2001) (p. 16)
Common near quarters, on the runway, and in open areas.
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1586)
Voucher cited: Forbes 171.M (BISH)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1586)
United States (other Pacific offshore islands)
Midway Atoll
Midway Atoll introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1586)
United States (other Pacific offshore islands)
Midway Atoll
Sand Island introduced
invasive
Starr, Forest/Starr, Kim/Loope, Lloyd (2008) (pp. B-12)
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
South America (Pacific rim)
South America (Pacific rim)
Chile (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim)
South America (Pacific rim)
Perú (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (Oregon) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (California) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (Washington) native
U.S. Dept. Agr., Nat. Res. Cons. 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
United States (continental except west coast)
United States (other states)
United States (other states) native
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

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This page was created on 28 JAN 2010 and was last updated on 29 JAN 2010.