Bromus diandrus

Roth
Common names: Great brome Ripgut grass
Introduced
Synonyms: Bromus rigidus var. gussonei Bromus rigidus Anisantha diandra
Treatment appears in FNA Volume 24. Treatment on page 224.
Please click on the illustration for a higher resolution version.
Illustrator: Cindy Roché

Copyright: Utah State University

Plants annual. Culms 20-90 cm, erect or decumbent, puberulent below the panicle. Sheaths softly pilose, hairs often retrorse or spreading; auricles absent; ligules 2-3 mm, glabrous, obtuse, lacerate or erose; blades 3.5-27 cm long, 1-9 mm wide, both surfaces pilose. Panicles 13-25 cm long, 2-12 cm wide, erect to spreading; branches 1-7 cm, stiffly erect to ascending or spreading, with 1 or 2 spikelets. Spikelets 25-70 mm, sides parallel or diverging distally, moderately laterally compressed, with 4-11 florets. Glumes smooth or scabrous, margins hyaline; lower glumes 15-25 mm, 1-3-veined; upper glumes 20-35 mm, 3-5-veined; lemmas 20-35 mm, linear-lanceolate, scabrous, 7-veined, rounded over the midvein, margins hyaline, apices bifid, acuminate, teeth 3-5 mm; awns 30-65 mm, straight, arising 1.5 mm or more below the lemma apices; anthers 0.5-1 mm. 2n = 42, 56.

Distribution

Wash., B.C., Del., D.C., Pacific Islands (Hawaii), Utah, N.J., N.Mex., Tex., N.Y., N.C., S.C., Nev., Va., Colo., Md., Calif., Ark., Ga., Ill., Okla., Ariz., Idaho, Mont., Oreg., Mass., Mo., La.

Discussion

Bromus diandrus is native to southern and western Europe. It is now established in North America, where it grows in disturbed ground, waste places, fields, sand dunes, and limestone areas. It occurs from southwestern British Columbia to Baja California, Mexico, and eastward to Montana, Colorado, Texas, and scattered locations in the eastern United States. The common name 'ripgut grass' indicates the effect it has on animals if they consume the sharp, long-awned florets of this species.

Bromus diandrus, as treated here, includes B. rigidus Roth. Sales (1993) reduced these two taxa to varietal rank, pointing out that the differences between them in panicle morphology and callus and scar shape are subtle enough that identification of many specimens beyond B. diandrus sensu lato is often impossible.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Bromus diandrus"
membranous +  and scarious +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Leon E. Pavlickf +
1 (?) +  and 3 (?) +
straight +
distinct +
subterminal +  and terminal +
geniculate +
1.5 cm15 mm <br />0.015 m <br /> (3 cm30 mm <br />0.03 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
3.5 cm35 mm <br />0.035 m <br /> (27 cm270 mm <br />0.27 m <br />) +
not evident +
cross +, linear +  and narrowly lanceolate +
1mm;9mm +
stiffly erect;ascending or spreading +
spikelike +
Great brome +  and Ripgut grass +
not branching +
decumbent +  and erect +
puberulent +
20 cm200 mm <br />0.2 m <br /> (90 cm900 mm <br />0.9 m <br />) +
not woody +
Wash. +, B.C. +, Del. +, D.C. +, Pacific Islands (Hawaii) +, Utah +, N.J. +, N.Mex. +, Tex. +, N.Y. +, N.C. +, S.C. +, Nev. +, Va. +, Colo. +, Md. +, Calif. +, Ark. +, Ga. +, Ill. +, Okla. +, Ariz. +, Idaho +, Mont. +, Oreg. +, Mass. +, Mo. +  and La. +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
4 +  and 11 +
terete +  and laterally compressed +
1-9(11)-veined +
always shorter +  and usually shorter +
lanceolate +
subtending +
pubescent +  and glabrous +
mucronate +  and acute +
unequal +
spreading +  and retrorse +
uncinate +
solid +  and hollow +
pubescent +  and glabrous +
rounded +  and linear-lanceolate +
2 cm20 mm <br />0.02 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
herbaceous +  and coriaceous +
lacerate +  and obtuse +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
membranous +
inconspicuous +
lanceolate +
fleshy +  and membranous +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
concealed +  and prominent +
2 +  and 1 +
hairy +  and glabrous +
well-developed +
reduced +
13cm +  and 25cm +
erect +  and spreading +
2 cm20 mm <br />0.02 m <br /> (12 cm120 mm <br />0.12 m <br />) +
dry +  and fleshy +
compressed +
Introduced +
1 +  and 60 +
not viviparous +
terete +  and moderately laterally compressed +
2.5 cm25 mm <br />0.025 m <br /> (7 cm70 mm <br />0.07 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Bromus rigidus var. gussonei +, Bromus rigidus +  and Anisantha diandra +
Bromus diandrus +
Bromus sect. Genea +
species +
membranous +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
2 cm20 mm <br />0.02 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
aquatic +  and terrestrial +