Bromus hordeaceus

L.
Common names: Lopgrass Brome mou
Introduced
Synonyms: Bromus mollis
Treatment appears in FNA Volume 24. Treatment on page 232.

Plants annual or biennial. Culms 2-70 cm, erect or ascending. Lower sheaths densely, often retrorsely, pilose; upper sheaths pubescent or glabrous; ligules 1-1.5 mm, hairy, obtuse, erose; blades 2-19 cm long, 1-4 mm wide, abaxial surfaces glabrous or hairy, adaxial surfaces hairy. Panicles 1-13 cm long, 1-4 cm wide, erect, usually ovoid, open, becoming dense, occasionally reduced to 1 or 2 spikelets; branches shorter than the spikelets, ascending to erect, straight or almost so. Spikelets (11) 14-20 (23) mm, lanceolate, terete to moderately laterally compressed; florets 5-10, bases concealed at maturity; rachilla internodes concealed at maturity. Glumes pilose or glabrous; lower glumes 5-7 mm, 3-5-veined; upper glumes 6.5-8 mm, 5-7-veined; lemmas 6.5-11 mm long, 3-5 mm wide, lanceolate, chartaceous, antrorsely pilose to pubescent, or glabrous proximally or throughout, 7-9-veined, lateral-veins prominently ribbed, rounded over the midvein, hyaline margins abruptly or bluntly angled, not inrolled at maturity, apices acute, bifid, teeth shorter than 1 mm; awns 6-8 mm, usually arising less than 1.5 mm below the lemma apices, straight to recurved at maturity; anthers 0.6-1.5 mm. Caryopses equaling or shorter than the paleas, thin, weakly inrolled to flat. 2n = 28.

Distribution

Colo., Nebr., Conn., N.J., N.Y., Wash., Va., Del., Wis., Idaho, Mont., Oreg., Wyo., Pacific Islands (Hawaii), N.Mex., Tex., La., N.C., Tenn., Pa., Okla., Calif., Nev., Mass., Maine, N.H., R.I., Alaska, Ill., Utah, Ark., Ind., Iowa, Ariz., Md., Ohio, Mo., Mich., N.Dak., S.Dak., Kans., S.C., Ky., Alta., B.C., Greenland, N.B., Nfld. and Labr. (Labr.), N.S., N.W.T., Ont., Que., Yukon

Discussion

Bromus hordeaceus is native to southern Europe and northern Africa. It is weedy, growing in disturbed areas such as roadsides, fields, sandy beaches, and waste places, and can be found in many locations in the Flora region, with the exception of the central Canadian provinces and most of the southeastern United States. Its origin is obscure. Ainouche et al. (1999) reviewed various suggestions, and concluded that at least one of its diploid ancestors may have been an extinct or undiscovered species related to B. caroli-henrici, a diploid species.

The four subspecies are usually morphologically distinct. Ainouche et al. (1999), however, found no evidence of genetic differentiation among them.

Selected References

None.

Key

1 Lemmas (7)8-11 mm long, usually pubescent or pilose. > 2
2 Awns more than 0.1 mm wide at the base, straight, erect; culms (3)10-70 cm long Bromus hordeaceus subsp. hordeaceus
2 Awns less than 0.1 mm wide at the base, often divaricate or recurved at maturity; culms 15-25(60) cm long Bromus hordeaceus subsp. molliformis
1 Lemmas 6.5-8(9) mm long, glabrous or pubescent. > 2
3 Culms (3)10-70 cm long; panicles up to 10 cm long, usually with more than 1 spikelet; lemmas usually glabrous; caryopses usually as long as the paleas; habitat various Bromus hordeaceus subsp. pseudothomineii
3 Culms 2-16 cm long; panicles 1-3 cm long, often reduced to 1 spikelet; lemmas pubescent or glabrous; caryopses shorter than the paleas; plants of maritime or lacustrine sands Bromus hordeaceus subsp. thotninei

"decumbent" is not a number.

... more about "Bromus hordeaceus"
hairy +  and glabrous +
membranous +  and scarious +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Leon E. Pavlickf +
divaricate +
3 (?) +  and 0 (?) +
straight +
distinct +
recurved +  and arising +
subterminal +  and terminal +
geniculate +
0 cm0 mm <br />0 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
2 cm20 mm <br />0.02 m <br /> (19 cm190 mm <br />0.19 m <br />) +
not evident +
cross +, linear +  and narrowly lanceolate +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
almost +  and straight +
ascending;erect +
spikelike +
Lopgrass +  and Brome mou +
not branching +
ascending +  and erect +
2 cm20 mm <br />0.02 m <br /> (70 cm700 mm <br />0.7 m <br />) +
not woody +
Colo. +, Nebr. +, Conn. +, N.J. +, N.Y. +, Wash. +, Va. +, Del. +, Wis. +, Idaho +, Mont. +, Oreg. +, Wyo. +, Pacific Islands (Hawaii) +, N.Mex. +, Tex. +, La. +, N.C. +, Tenn. +, Pa. +, Okla. +, Calif. +, Nev. +, Mass. +, Maine +, N.H. +, R.I. +, Alaska +, Ill. +, Utah +, Ark. +, Ind. +, Iowa +, Ariz. +, Md. +, Ohio +, Mo. +, Mich. +, N.Dak. +, S.Dak. +, Kans. +, S.C. +, Ky. +, Alta. +, B.C. +, Greenland +, N.B. +, Nfld. and Labr. (Labr.) +, N.S. +, N.W.T. +, Ont. +, Que. +  and Yukon +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
5 +  and 10 +
terete +  and laterally compressed +
1-9(11)-veined +
always shorter +  and usually shorter +
lanceolate +
subtending +
glabrous +  and pilose +
mucronate +  and acute +
unequal +
uncinate +
solid +  and hollow +
0.65 cm6.5 mm <br />0.0065 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
antrorsely pilose +  and pubescent or glabrous +
lanceolate +
herbaceous +  and coriaceous +
3mm +  and 5mm +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
membranous +
inconspicuous +
lanceolate +
fleshy +  and membranous +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
concealed +  and prominent +
2 +  and 1 +
hairy +  and glabrous +
well-developed +
reduced +
1cm +  and 13cm +
2 +  and 1 +
1 cm10 mm <br />0.01 m <br /> (4 cm40 mm <br />0.04 m <br />) +
dry +  and fleshy +
converging +  and parallel +
Introduced +
1 +  and 60 +
not viviparous +
terete +  and moderately laterally compressed +
1.4 cm14 mm <br />0.014 m <br /> (2 cm20 mm <br />0.02 m <br />) +
1 +  and 3 +
simple +  and compound +
2 (?) +  and 3 (?) +
Bromus mollis +
Bromus hordeaceus +
Bromus sect. Bromus +
species +
membranous +
1 cm10 mm <br />0.01 m <br /> (?) +
0.65 cm6.5 mm <br />0.0065 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
glabrous +  and pubescent +
biennial +  and annual +
aquatic +  and terrestrial +