Bromus hordeaceus
Bromus sect. Bromus
brome mou, lesser soft brome, lopgrass, soft brome, soft chess
2-70 cm, erect or ascending.
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.
(11)14-20(23) mm, lanceolate, terete to moderately laterally compressed;
florets 5-10, bases concealed at maturity;
rachilla internodes concealed at maturity.
with parallel or converging sides in outline, terete to moderately laterally compressed, with 4-30 florets.
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.
equaling or shorter than the paleas, thin, weakly inrolled to flat.
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.
glumes 3-5-veined;
upper glumes 5-9-veined;
lemmas elliptic, lanceolate, obovate, or rhombic, rounded over the midvein, apices subulate, acute, acuminate, or obtuse, notched, minutely bifid, or toothed, teeth shorter than 1 mm, apices sometimes split and the teeth appearing longer;
awns (0)1(3), straight or flexuous, recurved or divaricate.
= 28.
Bromus hordeaceus
Bromus sect. Bromus
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 sect. Bromus has about 40 species that are native to Eurasia, northern Africa, and Australia; 14 species have been introduced to the Flora region.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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 |
1. Lemmas inflated, 6-8 mm wide; unawned or with awns up to 1 mm long; spikelets ovate | B. briziformis |
1. Lemmas not inflated, 1-7 mm wide; awns 2-25 mm long, rarely absent; spikelet shape various. | → 2 |
2. Lemma margins inrolled at maturity; floret bases visible at maturity; rachilla internodes visible at maturity; caryopses sometimes thick, strongly inrolled. | → 3 |
2. Lemma margins not inrolled at maturity; floret bases concealed at maturity; rachilla internodes concealed at maturity; caryopses thin, weakly inrolled or flat. | → 3 |
3. Anthers 2.5-5 mm long; awns straight; spikelets often purple-tinged; lower leaf sheaths with soft, appressed hairs | B. arvensis |
3. Anthers 0.7-2 mm long; awns straight or flexuous; spikelets not purple-tinged; lower leaf sheaths glabrous, loosely pubescent and glabrate, or evenly covered with stiff hairs. | → 4 |
4. Lower leaf sheaths glabrous or loosely pubescent and glabrate; lemmas 6.5-8.5(10) mm long, margins evenly rounded; awns straight or flexuous | B. secalinus |
4. Lower leaf sheaths evenly covered with stiff hairs; lemmas 8-11.5 mm long, margins bluntly angled; awns straight | B. commutatus |
5. Lemmas 4.5-6.5 mm long, margins sharply angled; caryopses longer than the paleas | B. lepidus |
5. Lemmas 6.5-20 mm long, margins rounded or slightly to strongly angled; caryopses equaling or shorter than the paleas. | → 6 |
6. Awns arising less than 1.5 mm below the lemma apices, erect or weakly divaricate, not twisted at the base. | → 7 |
7. Panicle branches shorter than the spikelets; lemmas chartaceous, with prominent ribs over the veins, often concave between the veins; anthers 0.6-1.5 mm long | B. hordeaceus |
7. At least some panicle branches longer than the spikelets; lemmas coriaceous, veins obscure or distinct, not ribbed; anthers 0.7-5 mm long. | → 8 |
8. Lower leaf sheaths with soft, appressed hairs; anthers 2.5-5 mm long; panicles 11-30 cm long | B. arvensis |
8. Lower leaf sheaths with stiff hairs; anthers 0.7-3 mm long; panicles 4-16 cm long. | → 9 |
9. Anthers 0.7-1.7 mm long; rachilla internodes 1.5-2 mm long; lemmas 8-11.5 mm long, margins bluntly angled | B. commutatus |
9. Anthers 1.5-3 mm long; rachilla internodes 1-1.5 mm long; lemmas 6.5-8 mm long, margins rounded | B. racemosus |
6. Awns arising 1.5 mm or more below the lemma apices, erect to strongly divaricate, often twisted at the base. | → 10 |
10. Panicle branches shorter than the spikelets, slightly curved or straight, panicles erect. | → 11 |
11. At least the upper lemmas in each spikelet with 3 awns | B. danthoniae |
11. All lemmas 1-awned. | → 12 |
12. Lemmas 11-20 mm long; spikelets 20-50 mm long. | → 13 |
13. Spikelets usually single at the nodes; glumes glabrous or puberulent; panicles strongly contracted, even at maturity | B. caroli-henrici |
13. Spikelets often 2 or more at each node; glumes pilose; panicles contracted when immature, more open with age | B. lanceolatus |
12. Lemmas 6.5-11 mm long; spikelets 11-25 mm long. | → 14 |
14. Lemmas 1.5-2 mm wide; panicles obovoid, branches sometimes verticillate | B. scoparius |
14. Lemmas 3-5 mm wide; panicles usually ovoid | B. hordeaceus |
10. At least some panicle branches as long as or longer than the spikelets, sometimes sinuous; panicles nodding. | → 15 |
15. Lower glumes 7-10 mm long; upper glumes 8-12 mm long; panicle branches conspicuously sinuous; awns erect to weakly spreading; lemma margins rounded | B. arenarius |
15. Lower glumes 4-7 mm long; upper glumes 5-8 mm long; panicle branches sometimes sinuous; awns erect to strongly divergent; lemma margins slightly to strongly angled above the middle. | → 16 |
16. Anthers 2.5-5 mm long; spikelets often purple-tinged; culms 80-110 cm tall | B. arvensis |
16. Anthers 1-1.5 mm long; spikelets not purple-tinged; culms 20-70 cm tall. | → 17 |
17. Lemmas with hyaline margins 0.3-0.6 mm wide, slightly angled above the middle; branches somewhat drooping, sometimes sinuous, often with more than 1 spikelet | B. japonicus |
17. Lemmas with hyaline margins 0.6-0.9 mm wide, strongly angled above the middle; branches not drooping or sinuous, usually with 1 spikelet | B. squarrosus |
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