Pacific Island Ecosystems at Risk (PIER)

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Bromus diandrus
Roth, Poaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Bromus rigidus Roth

Common name(s): [more details]

Chinese: ying que mai

English: broncho grass, giant brome, great brome, ripgut brome, ripgut grass, slands grass

French: brome raide

Spanish: barba de macho

Habit:  grass

Description: 

Bromus diandrus Roth:  "Annuals, 20-90 cm, loosely tufted or consisting of a solitary culm. Leaf-sheath with soft, short, spreading hairs; upper sheaths ± glabrous near base. Ligule 1.5-4 mm, denticulate to lacerate. Leaf-blade 4-30 cm x 2-7 mm, with short, ± scattered hairs, scabrid near acute tip. Culm 10-65 cm, erect or ascending, internodes with very short hairs below nodes and below panicle. Panicle 10-28 cm, very lax and nodding; branches spreading, slender, scabrid, tipped by 1-(2) spikelets. Spikelets 5.5-9.5 cm, 5-8-flowered, oblong-lanceolate to later wedge-shaped and gaping, greyish green to purplish. Glumes unequal, very narrow, acuminate, membranous, glabrous, but sparsely scabrid on keels and nerves in upper 1/2; lower 13-22 mm, 1-(3)-nerved, upper 20-30 mm, 3-(5)-nerved. Lemma 20-35 mm, 7-nerved, rounded, lanceolate, minutely scabrid, tapering to 2 acute to acuminate, hyaline, smooth to finely scabrid lobes 4-5 mm; awn 30-60 mm. Palea c. 2/3 length of lemma, keels sparsely ciliate. Callus with minute hairs. Rachilla 4-6 mm, finely, minutely scabrid. Stamens 2-3; anthers 1-3 mm. Caryopsis 11-13 x 1.5-2.8 mm"  (Edgar & Connor, 2000; p. 362).

Description from GrassBase.

Bromus diandrus Roth var. rigidus (Roth) Sales:  "Annuals, culms 4-7 (-9) dm tall, solitary or sparsely tufted, pubescent for ca. 15 cm below panicle.  Sheaths 2-10 cm long, pilose; ligule 2-4 (-5.5) mm long, membranous, erose-lacerate; blades flat, 2-6 (-8) mm wide, sometimes involute, pilose, auricles absent.  Inflorescences paniculate, (7-) 10-20 cm long, open, the branches elongate, erect or spreading, sometimes the lowermost reflexed; spikelets (3) 4-6 (-8)-flowered, (28-) 33-40 (-43) mm long; glumes scabrous, linear to narrowly lanceolate, first glume 13-18 (-22) mm long, 1 (-3)-nerved; lemmas (22-) 25-30 mm long, 1-1.5 mm wide in side view, scabrous to puberulent, the narrow apical teeth 3-6 mm long, awns (30-) 35-60 mm long; palea slightly shorter than lemma, ciliate on the 2 keels, adhering to caryopsis.  Caryopsis golden brown, narrow, 10-15 mm long"  (Wagner et al., 1999; p. 1508).

Habitat/ecology:  In Hawai‘i, "naturalized and common in pastures, subalpine forest and shrubland, and disturbed areas, (5-) 550-2,270 m"  (Wagner et al., 1999; p. 1508).  "In Chile this species grows in the following environmental conditions:  Low altitude, interior valleys; coastal mountains, 500-2000 m; coastal areas, 0-500 m.  Somewhat dry areas where the drought may last 3-5 months, precipitations of 400 - 800 mm. are concentrated in winter.  Fully exposed to the sun, level areas or slopes facing north"  (Chileflora).

Propagation:  Seed

Native range:  The Mediterranean region (Wagner et al., 1999; p. 1508).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia (Pacific offshore islands)
Lord Howe Island
Lord Howe Island introduced
invasive
Orchard, Anthony E., ed. (1994) (p. 22)
"A fairly common weed of poor pastures, roadsides etc." Vouchers cited: R.D. Hoogland 8658 (CANB), P.S. Green 1643 (A, K), A.C. Beauglehole 5430 (CANB, MEL)
Australia (Pacific offshore islands)
Norfolk Islands
Norfolk Island introduced
invasive
Orchard, Anthony E., ed. (1994) (p. 12)
"A fairly common weed of poor pastures, roadsides etc." Vouchers cited: P.S. Green 1478 (A), W.R. Sykes 772/87 (CHR), W. Laing (CHR)
Chile (offshore islands)
Juan Fernández Islands
Isla Más a Tierra (Robinson Crusoe Island) introduced
invasive
Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands)
Juan Fernández Islands
Isla Más a Tierra (Robinson Crusoe Island) introduced
invasive
Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 460, 463, 551)
Voucher cited: Danton I(5/192)1525
Chile (offshore islands)
Juan Fernández Islands
Isla Más Afuera (Alejandro Selkirk Island) introduced
invasive
Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands)
Juan Fernández Islands
Isla Más Afuera (Alejandro Selkirk Island) introduced
invasive
Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 460, 463, 551)
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1508)
As Bromus rigidus [=Bromus diandrus Roth var. rigidus (Roth) Sales]; voucher cited: Rock 8403 (BISH)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1508)
As Bromus rigidus [=Bromus diandrus Roth var. rigidus (Roth) Sales]
State of Hawaii
Hawaiian Islands
Lāna‘i Island introduced
invasive
Oppenheimer, Hank (2008) (p. 32)
Voucher cited: Oppenheimer, Perlman & Tangalin H30714 (BISH, PTBG)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Herbarium Pacificum Staff (1999) (p. 7)
East Maui. As Bromus rigidus [=Bromus diandrus Roth var. rigidus (Roth) Sales]; voucher cited: C. Imada, W. Char & C. Morden 98-11
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Starr, Forest/Starr, Kim (2011) (p. 32)
East Maui. Voucher cited: Starr & Starr 090628-01 (BISH)
New Zealand (offshore islands)
Kermadec Islands
Kermadec Islands introduced
invasive
Edgar, E./Connor, H. (2000) (p. 362)
"Roadsides and waste ground, often in sandy ground".
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. 35)
Chile (continental)
Chile
Chile (Republic of) introduced
invasive
Belov, Michail (2013)
China
China
China (People's Republic of) introduced
invasive
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
As Bromus rigidus Roth. Streamsides, moist places; ca. 1000 m. Jiangxi
China
China
China (People's Republic of)   Hafliger, Ernst/Scholz, Hildemar (1980) (p. 41)
As Bromus rigidus [=Bromus diandrus Roth var. rigidus (Roth) Sales]
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Edgar, E./Connor, H. (2000) (p. 362)
"Roadsides and waste ground, often in sandy ground".
Taiwan
Taiwan Island
Taiwan Island introduced
invasive
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
As Bromus rigidus Roth. Streamsides, moist places; ca. 1000 m.


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This page was created on 10 FEB 2007 and was last updated on 10 JAN 2011.