The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

brome mou, lesser soft brome, lopgrass, soft brome, soft chess

Mexican brome

Habit Plants annual or biennial. Plants perennial; not rhizomatous.
Culms

2-70 cm, erect or ascending.

40-90 cm, erect;

nodes (3)4-7(8), these and the internodes pubescent or glabrous.

Sheaths

glabrous or pilose, midrib of the culm leaves abruptly narrowed just below the collar;

auricles often present on the lower leaves;

ligules to 1 mm, truncate;

blades 14-22(26) cm long, to 6 mm wide, flat, glabrous or pilose, not glaucous.

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.

10-20 cm, open, nodding;

branches ascending or spreading.

Spikelets

(11)14-20(23) mm, lanceolate, terete to moderately laterally compressed;

florets 5-10, bases concealed at maturity;

rachilla internodes concealed at maturity.

(14)15-30 mm, elliptic to lanceolate, terete to moderately laterally compressed, with 4-12 florets.

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.

usually pubescent, rarely glabrous;

lower glumes 5-6 mm, 1-3-veined;

upper glumes 6-8 mm, 3-veined, sometimes mucronate;

lemmas 7-10 mm, elliptic to lanceolate, rounded over the midvein, backs and margins pubescent, apices acute to obtuse, entire;

awns 1-3(5) mm, straight, arising less than 1.5 mm below the lemma apices;

anthers 2-4 mm.

Caryopses

equaling or shorter than the paleas, thin, weakly inrolled to flat.

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.

2n

= 28.

= 14.

Bromus hordeaceus

Bromus anomalus

Distribution
from FNA
AK; AR; AZ; CA; CO; CT; DE; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MO; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; WA; WI; WY; HI; AB; BC; LB; NB; NS; NT; ON; QC; YT; Greenland
[WildflowerSearch map]
[BONAP county map]
from FNA
NM; TX; AB; BC; SK
[BONAP county map]
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.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Bromus anomalus grows on rocky slopes in western Texas and adjacent Mexico. Many records of this species in the Flora region are here treated as B. porteri, a closely related species that has sometimes been included in B. anomalus. The main difference is that B. anomalus has auricles, and culm leaves with midribs that are narrowed just below the collar.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

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
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
subsp. molliformis
1. Lemmas 6.5-8(9) mm long, glabrous or pubescent.
→ 3
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
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
subsp. thotninei
Source FNA vol. 24, p. 232. FNA vol. 24, p. 213.
Parent taxa Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Bromus Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Bromopsis
Sibling taxa
B. aleutensis, B. anomalus, B. arenarius, B. arizonicus, B. arvensis, B. berteroanus, B. briziformis, B. carinatus, B. caroli-henrici, B. catharticus, B. ciliatus, B. commutatus, B. danthoniae, B. diandrus, B. erectus, B. frondosus, B. grandis, B. hallii, B. inermis, B. japonicus, B. kalmii, B. laevipes, B. lanatipes, B. lanceolatus, B. latiglumis, B. lepidus, B. madritensis, B. maritimus, B. mucroglumis, B. nottowayanus, B. orcuttianus, B. pacificus, B. polyanthus, B. porteri, B. pseudolaevipes, B. pubescens, B. pumpellianus, B. racemosus, B. ramosus, B. richardsonii, B. riparius, B. rubens, B. scoparius, B. secalinus, B. sitchensis, B. squarrosus, B. sterilis, B. suksdorfii, B. tectorum, B. texensis, B. vulgaris
B. aleutensis, B. arenarius, B. arizonicus, B. arvensis, B. berteroanus, B. briziformis, B. carinatus, B. caroli-henrici, B. catharticus, B. ciliatus, B. commutatus, B. danthoniae, B. diandrus, B. erectus, B. frondosus, B. grandis, B. hallii, B. hordeaceus, B. inermis, B. japonicus, B. kalmii, B. laevipes, B. lanatipes, B. lanceolatus, B. latiglumis, B. lepidus, B. madritensis, B. maritimus, B. mucroglumis, B. nottowayanus, B. orcuttianus, B. pacificus, B. polyanthus, B. porteri, B. pseudolaevipes, B. pubescens, B. pumpellianus, B. racemosus, B. ramosus, B. richardsonii, B. riparius, B. rubens, B. scoparius, B. secalinus, B. sitchensis, B. squarrosus, B. sterilis, B. suksdorfii, B. tectorum, B. texensis, B. vulgaris
Subordinate taxa
B. hordeaceus subsp. hordeaceus, B. hordeaceus subsp. molliformis, B. hordeaceus subsp. pseudothomineii, B. hordeaceus subsp. thotninei
Synonyms B. mollis
Name authority L. Rupr. ex E. Fourn.
Web links