Bromus diandrus Roth, Poaceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  yes

Threat only at high elevations?  no

Other Latin names:  Bromus rigidus Roth [=Bromus diandrus Roth var. rigidus (Roth) Sales]

Common name(s): [more details]

English: bronchograss, 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 World Grass Species.

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).

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) "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) "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)
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	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
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)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 41) As Bromus rigidus [=Bromus diandrus Roth var. rigidus (Roth) Sales]
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".

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

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

References:

Edgar, E./Connor, H. 2000. Flora of New Zealand, vol. V: Gramineae. Manaaki Whenua Press. .

Hafliger, Ernst/Scholz, Hildemar. 1980. Grass weeds, vol. 2. CIBA-GEIGY Ltd., Basle, Switzerland. 137 pp. + plates.

Herbarium Pacificum Staff. 1999. New Hawaiian plant records for 1998. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1998. Part 1: Articles. Bishop Museum Occasional Papers. 58:3-11.

Orchard, Anthony E., ed. 1994. Flora of Australia. Vol. 49, Oceanic islands 1. Australian Government Publishing Service, Canberra.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).