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1 Lemmas compressed and strongly keeled (the whole spikelet thus strongly laterally flattened); first glume 3-9-nerved; [section Ceratochloa] |
1 Lemmas rounded or weakly keeled (the whole spikelet therefore terete to somewhat laterally flattened); first glume either 3-5-nerved or 1-3-nerved. |
2 First glume 3-5 nerved (at least 3 nerves well-developed). |
3 Lemma awn 2-3 mm long; plant perennial; [native species of dry woodlands]; [section Bromopsis] |
3 Lemma awn 3-12 mm long (or 0-6 mm long in B. secalinus); plant annual; [introduced species of disturbed habitats]; [section Bromus]. |
4 Panicle compact, the lateral branches erect or ascending, the pedicels < 10 mm long (shorter than the spikelets) |
5 Lemmas 3-5 mm wide; inflorescence ovoid in outline |
5 Lemmas 1.5-2 mm wide; inflorescence obovoid in outline |
4 Panicle relatively open, the lateral branches erect, ascending, or spreading, the pedicels > 15 mm long (longer than the spikelets). |
6 Margins of the lemmas involute in fruit, wrapping around the grain, exposing the rachilla |
7 Spikelets often purple-tinged; lower leaf sheaths bearing soft, appressed hairs; lemma awns 6-11 mm long |
7 Spikelets not purple-tinged; lower leaf sheaths glabrous, loosely pubescent and glabrate, or evenly pilose; lemma awns 0-6 mm (sometimes awns absent or rudimentary) |
6 Margins of the lemmas gaping, overlapping in fruit. |
8 Panicle branches erect or ascending, relatively stiff and straight |
8 Panicle branches spreading (at least the lower), either relatively stiff and straight, or flexuous and lax. |
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9 Panicle branches flexuous and lax; lemma awns 7-15 mm long, flexuous |
2 First glume 1 (-3) nerved (only 1 nerve well-developed). |
10 Longer lemma awns 10-60 mm long; plants annual; [introduced species of disturbed habitats]; [section Genea]. |
11 Panicle dense, spikelike |
11 Panicle open, not spikelike. |
12 First glume 13-20 mm long; second glume 20-30 mm long; lemma awns 35-60 mm long |
12 First glume 5-14 mm long; second glume 8-17 mm long; lemma awns 10-30 mm long. |
13 First glume 7-14 mm long; second glume 9-17 mm long; lemma awns 18-30 mm long |
13 First glume 5-7 mm long; second glume 8-11 mm long; lemma awn (7-) 10-17 mm long |
10 Longer lemma awns 1-6 (-8) mm long; plants perennial; [native and introduced species, collectively of disturbed and natural habitats]; [section Bromopsis]. |
14 Plants with creeping rhizomes, forming clonal colonies; both surfaces of leaves glabrous or glabrescent |
14 Plants not strongly rhizomatous, the stems solitary or tufted; surfaces of leaf blades usually pubescent (sometimes sparsely so). |
15 Pedicels erect or ascending, mostly shorter than the spikelet; leaves 2-3 mm wide; [introduced, of disturbed habitats] |
15 Pedicels ascending at first, later arching-drooping, mostly longer than the spikelet; leaves 4-15 mm wide; [mostly native, mostly of forests]. |
16 Lemmas glabrous (or very minutely pubescent) on the back, hairy along the lower margins with long hairs |
16 Lemmas either uniformly hairy over the entire back-surface (or rarely entirely glabrous), or hairy across at least the lower half of the back-surface. |
17 Culms with 2-4 leaves; glumes usually glabrous ( scabridulous on the veins); [rare waif, if indeed in our region] |
17 Culms with 6-20 leaves; glumes pubescent (sometimes glabrous in some species); [natives, collectively widespread] |
18 Culms with 10-20 leaves, often weak and leaning or reclining; junction of sheaths and base of leaf blades with 2 well-developed flanges prolonged into auricles or divergent spurs; second glume primarily 5-nerved; flowering late, with anthesis Aug-Oct |
18 Culms with 6-10 leaves, erect; junction of sheaths and base of leaf blades lacking flanges or auricles; second glume primarily 3-nerved; flowering earlier, anthesis from May-Aug. |
19 Lower surface of leaf with a conspicuous satiny sheen (when fresh); summit of sheath opposite the ligule with a conspicuous tuft of hairs |
19 Lower surface of leaf lacking a conspicuous satiny sheen; summit of sheath opposite the ligule lacking a conspicuous tuft of hairs |