FNA: Muhlenbergia vs. Muhlenbergia pectinata

1. Plants annual [for opposite lead, see p. 147].	→ 2
2. Lemmas unawned or mucronate, the mucros to 1 mm long.	→ 3
3. Glumes strigulose, at least on the margins or towards the apices, the hairs 0.1-0.3 mm long.	→ 4
4. Pedicels of most spikelets strongly curved below the spikelets, often through 90° or more; anthers olivaceous, 0.6-1.2 mm long	M. sinuosa
4. Pedicels of most spikelets straight to somewhat curved below the spikelets, rarely curved through 90°; anthers purplish, 0.2-0.7 mm long.	→ 5
5. Sheaths and culm internodes strigulose; lemmas 1.3-2 mm long, the apices acute to acuminate, mucronate or shortly awned	M. texana
5. Sheaths and culm internodes glabrous, sometimes scabridulous; lemmas 0.8-1.5 mm long, the apices obtuse to subacute, unawned	M. minutissima
3. Glumes glabrous.	→ 6
6. Panicles contracted, less than 0.5 cm wide; branches closely appressed at maturity; culms often rooting at the lower nodes	M. filiformis
6. Panicles open or diffuse, 0.6-11 cm wide; branches spreading at maturity; culms not rooting at the lower nodes.	→ 7
7. Primary panicle branches 0.5-3.2 cm long; pedicels stout, 1-3 mm long, 0.5-1.5 mm thick; lemmas mottled, with greenish-black and greenish-white areas	M. ramulosa
7. Primary panicle branches 0.4-6.2 cm long; pedicels delicate, 0.2-10 mm long, about 0.02 mm thick; lemmas not mottled, purplish, plumbeous, or brownish.	→ 8
8. Primary panicle branches diverging 80-100° from the rachises; branches not developing below the lower leaf nodes; ligules with lateral lobes (vertical extensions of the sheath margins); plants truly annual	M. fragilis
8. Primary panicle branches diverging less than 80° from the rachises; branches developing below the lower leaf nodes; ligules without lateral lobes; plants perennial but often appearing annual	M. uniflora
2. Lemmas awned, the awns 1-32 mm long.	→ 9
9. Upper glumes 2- or 3-veined, apices 2- or 3-toothed, not awned.	→ 10
10. Lemma awns olive-green, sinuous to curled; lemmas widest near the middle, 1.7-2.2 mm long	M. crispiseta
10. Lemma awns purplish, flexuous; lemmas widest near the base, 1.4-4.2 mm long	M. peruviana
9. Upper glumes 1-veined or veinless, entire, erose, or awned.	→ 11
11. Lower glumes 2-veined, minutely to deeply bifid, the teeth aristate or with awns to 1.8 mm long; spikelets often in sessile-pedicellate pairs; disarticulation at the base of the pedicels.	→ 12
12. Glumes subequal to the lemmas; lemmas 2.5-4.5 mm long, those of the upper spikelets with awns 6-15 mm long	M. depauperata
12. Glumes up to 2/3 as long as the lemmas; lemmas 3.5-6 mm long, those of the upper spikelets with awns 10-20 mm long	M. brevis
11. Lower glumes, if present, veinless or 1-veined, not bifid, unawned or with a single awn; spikelets borne singly; disarticulation above the glumes.	→ 13
13. Lemma awns 1-5 mm long.	→ 14
14. Glumes 0.1-0.3 mm long, the lower glumes often almost absent; ligules 0.2-0.5 mm	M. schreberi
14. Glumes 0.8-1.8 mm long; lower glumes 0.8-1.6 mm long; ligules 0.9-2.5 mm long.	→ 15
15. Pedicels 2-7 mm long, usually longer than the florets, usually divergent; lemmas 1.3-2 mm long; lemma awns 0.1-1(2) mm long; caryopses 0.8-1 mm long; paleas minutely appressed-pubescent on the lower 1/2, 1.3-2 mm long	M. texana
15. Pedicels 1-2(3) mm long, usually shorter than the florets and appressed to the branches; lemmas (1.7)1.9-2.5 mm long; lemma awns 1.2-3.5 mm long; caryopses 1.3-2.3 mm long; paleas glabrous, 1.8-2.4 mm long	M. eludens
13. Lemma awns 10-32 mm long.	→ 16
16. Panicles secund; primary branches with 2-5 spikelets; secondary branches not developed; spikelets dimorphic with respect to the glumes, the glumes of the proximal spikelet on each branch subequal, to 0.7 mm long, orbicular and unawned, those of the distal spikelets evidently unequal, the lower glumes to 8 mm long and usually avned, the upper glumes orbicular, some times awned	M. diversiglumis
16. Panicles not secund; primary branches always with more than 2 spikelets, usually with more than 5; secondary branches well-developed; spikelets monomorphic with respect to the glumes.	→ 17
17. Ligules 0.3-0.9 mm long, membranous and ciliate; distal portion of the sheath margins with hairs to 1 mm long; lemmas subulate to lanceolate, with a scabrous line between the midvein and lateral veins, giving the lemmas a 5-veined appearance	M. pectinata
17. Ligules 1-3(5) mm long, hyaline to membranous, often lacerate; sheath margins glabrous, even distally; lemmas lanceolate, smooth over most of their length, scabridulous to scabrous distally, not appearing 5-veined.	→ 18
18. Cleistogamous panicles not present in the axils of the lower cauline leaves; upper glumes 1.5-2.8 mm long, acute	M. tenuifolia
18. Cleistogamous panicles of 1-3 florets present in the axils of the lower cauline leaves; upper glumes 0.6-2 mm long, obtuse to subacute.	→ 19
19. Lemmas 2.5-3.8(5.3) mm long; glumes 0.4-1.3 mm long; ligules 1-2 mm long	M. microsperma
19. Lemmas 4-6.2(7.5) mm long; glumes 1-2 mm long; ligules 1.5-3 mm long	M. appressa
1. Plants perennial [for opposite lead, see p. 146].	→ 20
20. Plants rhizomatous, usually not cespitose; rhizomes scaly and creeping [for opposite lead, see p. 149].	→ 21
21. Panicles open, (2)4-20 cm wide; panicle branches capillary (0.05-0.1 mm thick), diverging 30-100° from the rachises at maturity.	→ 22
22. Lemmas awned, awns 1-12(20) mm long.	→ 23
23. Blades stiff and pungent; lemma awns 1-1.5(2) mm long, straight; primary branches of the panicles appearing fascicled in immature plants	M. pungens
23. Blades not stiff and pungent; lemma awns 4-12(20) mm long, flexuous; primary branches of the panicles not appearing fascicled	M. arsenei
22. Lemmas unawned, sometimes mucronate with mucros to 0.3 mm long.	→ 24
24. Culms compressed-keeled; blades conduplicate; panicles cylindrical, 4-8 cm wide	M. torreyana
24. Culms terete to somewhat compressed-keeled near the base; blades usually flat, occasionally conduplicate; panicles ovoid, 4-16 cm wide.	→ 25
25. Ligules 0.5-2 mm long, hyaline, with well-developed lateral lobes; blade margins and midveins prominent, white, thick	M. arenacea
25. Ligules 0.2-1 mm long, ciliate, without lateral lobes; blade margins and midveins not prominent, greenish, not particularly thick	M. asperifolia
21. Panicles contracted, 0.1-2(3) cm wide; panicle branches more than 0.1 mm thick, appressed or diverging up to 30(40)° from the rachises at maturity.	→ 26
26. Culms 100-300 cm tall, 3-6 mm thick, woody and bamboolike	M. dumosa
26. Culms 4-100(140) cm tall, 0.5-2(3) mm thick, herbaceous, not bamboolike.	→ 27
27. Blades 0.2-2(2.6) mm wide, flat, involute, or folded at maturity.	→ 28
28. Lemmas awned, the awns 1-25 mm long.	→ 29
29. Lemmas pubescent for 3/4 their length, the hairs about 1.5 mm long	M. curtifolia
29. Lemmas scabridulous or pubescent for no more than 1/2 their length, the hairs often less than 1.5 mm long.	→ 30
30. Lemma awns generally less than 4(6) mm long	M. glauca
30. Lemma awns 4-25 mm long.	→ 31
31. Lemmas and paleas mostly glabrous, the calluses with a few short hairs; ligules with lateral lobes, the lobes 1.5-3 mm longer than the central portion; culms erect; plants tightly cespitose at the base; sheaths and blades commonly with dark brown necrotic spots	M. pauciflora
31. Lemma midveins and margins and paleas appressed-pubescent on the lower 1/3 – 2/3; ligules without lateral lobes or with lobes less than 1.5 mm longer than the central portion; culms decumbent; plants loosely cespitose at the base; sheaths and blades without necrotic spots.	→ 32
32. Anthers orange, 1.5-2 mm long; lemmas elliptic, 2-3.5 mm long, the awns 10-20(25) mm long; panicles 0.3-1.8 cm wide	M. polycaulis
32. Anthers purple, 1.3-3 mm long; lemmas lanceolate, 3.5-5 mm long, the awns 4-12(20) mm long; panicles 1-3(5) cm wide	M. arsenei
28. Lemmas unawned, mucronate, or shortly awned, the awns to 1 mm long.	→ 33
33. Lemmas and paleas pubescent, the hairs 0.4-1.2 mm long.	→ 34
34. Glumes acuminate, usually awned, the awns to 1.5 mm long; anthers orange; blades flat to involute distally, never arcuate	M. glauca
34. Glumes acute, neither mucronate nor awned; anthers yellow, dark green, or purple; blades tightly involute, often arcuate.	→ 35
35. Lemmas 2.6-4 mm long; glumes nearly as long as the lemmas; anthers 2.1-2.3 mm long	M. thurberi
35. Lemmas 1.4-2.5 mm long; glumes 1/2 - 2/3 as long as the lemmas; anthers 0.9-1.4 mm long	M. villiflora
33. Lemmas and paleas scabrous, glabrous, or with hairs less than 0.3 mm long.	→ 36
36. Glumes more than 1/2 as long as the lemmas; lemmas 2.6-4.2 mm long, attenuate	M. repens
36. Glumes 1/2 as long as the lemmas or less; lemmas 1.3-3.1 mm long; not attenuate.	→ 37
37. Ligules 0.2-0.8 mm long; panicles usually partially included, the rachises usually visible between the branches	M. utilis
37. Ligules 0.8-3 mm long; panicles exserted, the rachises usually hidden by the branches	M. richardsonis
27. Blades (1.5)2-15 mm wide, flat at maturity.	→ 38
38. Glumes awn-tipped, 3-8 mm long (including the awns), about 1.3-2 times longer than the lemmas.	→ 39
39. Internodes dull, puberulent, usually terete, rarely keeled; culms seldom branched above the base; ligules 0.2-0.6 mm long; anthers 0.8-1.5 mm long	M. glomerata
39. Internodes smooth and polished for most of their length, elliptic in cross section and strongly keeled; culms much branched above the base; ligules 0.6-1.7 mm long; anthers 0.4-0.8 mm long	M. racemosa
38. Glumes unawned or awn-tipped, 0.4-4 mm long (including the awns), from shorter than to about 1.2 times longer than the lemmas.	→ 40
40. Lemmas usually completely glabrous, rarely with a few appressed hairs.	→ 41
41. Culms 30-100 cm tall, bushy and much branched above; axillary panicles common, partly included or exserted from the sheaths; lemmas shiny, stramineous or purplish, not mottled; anthers 0.3-0.5 mm long	M. glabrifloris
41. Culms 5-30 cm tall, often mat-forming; axillary panicles not present; lemmas dark greenish or plumbeous, sometimes mottled; anthers 0.9-1.6 mm long	M. richardsonis
40. Lemmas with hairs, these sometimes restricted to the callus.	→ 42
42. Lemma bases with hairs about as long as the florets, usually 2-3.5 mm long	M. andina
42. Lemma bases glabrous or with hairs shorter than the florets, usually shorter than 1.5 mm.	→ 43
43. Glumes unequal in length, the lower glumes 0.4-1.5 mm long, the upper glumes 0.8-1.9 mm long	M. ×curtisetosa
43. Glumes subequal in length, 1-4 mm long.	→ 44
44. Axillary panicles often present, always partly included in the sheaths; internodes smooth, shiny.	→ 45
45. Ligules 0.2-0.6 mm long; leaves of the lateral branches often shorter and narrower than those of the main branches; glumes 1.4-2 mm long, 1/3– 2/3 as long as the lemmas	M. bushii
45. Ligules 0.7-1.7 mm long; leaves of the lateral branches similar in length and width to those of the main branches; glumes 2-4 mm long, about as long as the lemmas	M. frondosa
44. Axillary panicles, if present, exserted on elongated peduncles; internodes smooth, scabrous, or pubescent, sometimes smooth and shiny.	→ 46
46. Glumes much shorter than the lemmas, acute.	→ 47
47. Anthers 0.4-1 mm long; lemmas unawned, or with a short awn less than 1 mm long; internodes and sheaths glabrous	M. sobolifera
47. Anthers 1.1-2.2 mm long; lemmas awned (occasionally unawned), the awns to 12 mm long; internodes (and usually the base of the sheaths) pubescent	M. tenuiflora
46. Glumes nearly as long as or longer than the lemmas, acuminate.	→ 48
48. Anthers 1-1.7 mm long; sheaths scabrous; lemma awns 0.2-2.2 mm long; restricted to the Transverse Ranges of southern California	M. californica
48. Anthers 0.3-0.8 mm long, sheaths smooth for most of their length; lemma awns to 18 mm long; widespread species, but not known from southern California.	→ 49
49. Ligules 0.4-1 mm long; panicles dense; pedicels up to 2 mm long; anthers 0.3-0.5 mm long	M. mexicana
49. Ligules 1-2.5 mm long; panicles not dense, pedicels 0.8-3.5 mm long; anthers 0.4-0.8 mm long	M. sylvatica
20. Rhizomes absent; plants cespitose or bushy [for opposite lead, see p. 147].	→ 50
50. Upper glumes usually 3-veined and 3-toothed; old sheaths flattened, ribbonlike or papery, sometimes spirally coiled.	→ 51
51. Lemmas unawned, mucronate, or with awns to 5 mm long.	→ 52
52. Lower glumes awned, the awns to 1.6 mm long; blades 2-6 cm long, filiform, tightly involute, sharp-tipped	M. filiculmis
52. Lower glumes unawned; blades (5)6-12 cm long, flat or loosely involute to subfiliform, not sharp-tipped	M. jonesii
51. Lemmas awned, the awns (2)6-27 mm long.	→ 53
53. Upper glumes as long as or longer than the lemmas, the apices acuminate to acute, occasionally minutely 3-toothed; old sheaths conspicuously spirally coiled	M. straminea
53. Upper glumes 1/3 – 2/3 as long as the lemmas, the apices truncate to acute, 3-toothed; old sheaths occasionally spirally coiled	M. montana
50. Upper glumes usually 1-veined, (rarely 2- or 3-veined), rounded, obtuse, acute, or acuminate, entire or erose; old sheaths not flattened or papery, never spirally coiled.	→ 54
54. Panicles loosely contracted, open, or diffuse, (1)2-40 cm wide; panicle branches usually not appressed at maturity, often naked basally [for opposite lead, see p. 152].	→ 55
55. Culms arising from the bases of old depressed culms; plants loosely matted, delicate; lemmas 1.2-2 mm long, unawned	M. uniflora
55. Culms not arising from the bases of old depressed culms; plants cespitose, not delicate; lemmas 2-5 mm long, awned or unawned.	→ 56
56. Lemmas unawned or with awns to 4(6) mm long.	→ 57
57. Basal sheaths laterally compressed, usually keeled.	→ 58
58. Glumes longer than the lemmas; ligules 10-25 mm long, membranous throughout; lemmas 2-3 mm long, usually awned, the awns to 15 mm long, occasionally unawned	M. emersleyi
58. Glumes shorter than the lemmas; ligules 3-12 mm long, firm and brown near the base, membranous distally; lemmas 3-4.2 mm long, awned, the awns 0.5-4 mm long	M. ×involuta
57. Basal sheaths rounded to somewhat flattened, not keeled.	→ 59
59. Culms 10-60(70) cm tall, somewhat decumbent; blades 0.5-10(16) cm long.	→ 60
60. Blade margins and midveins conspicuous, thick, white, and cartilaginous; ligules 1-2 mm long	M. arizonica
60. Blade margins not conspicuously thickened, greenish; ligules 2-9 mm long.	→ 61
61. Blades arcuate, 0.3-0.9 mm wide, 1-3(5) cm long; usually no culm nodes exposed; most leaf blades reaching no more than 1/5 of the plant height	M. torreyi
61. Blades not arcuate, 1-2.2 mm wide, 4-10(16) cm long; 1 or more culm nodes exposed; leaf blades reaching 1/4 - 1/2 of the plant height	M. arenicola
59. Culms 40-160 cm tall, erect from the base; blades (8)10-100 cm long.	→ 62
62. Pedicels 0.1-2.5 mm long, usually shorter than the florets; glumes usually longer than the florets; ligules 10-30 mm long; panicle branches not capillary, appressed or spreading up to 60° from the rachises, the lower branches with 30-60 spikelets	M. longiligula
62. Pedicels 3-50 mm long, longer than the florets; glumes usually shorter than the florets; ligules 1.8-10 mm long; panicle branches capillary, spreading 30-100° from the rachises, the lower branches with 5-20 spikelets.	→ 63
63. Panicles about as long as wide, not diffuse, 10-20(30) cm long; branches and pedicels stiff or flexible	M. reverchonii
63. Panicles longer than wide, diffuse, 15-60 cm long; branches and pedicels flexible.	→ 64
64. Glumes more than 1/2 as long as the lemmas; lemmas usually unawned, if awned, the awns no more than 3 mm long	M. expansa
64. Glumes less than 1/2 as long as the lemmas; lemmas usually awned, the awns to 18 mm long	M. capillaris
56. Lemma awns 6-35 mm long.	→ 65
65. Plants conspicuously branched, bushy in appearance; culms wiry, with geniculate, stiff, widely divergent branches	M. porteri
65. Plants not conspicuously branched, not bushy in appearance, usually typical bunchgrasses; culms not wiry, when branched, the branches not both geniculate and widely divergent.	→ 66
66. Basal sheaths laterally compressed, commonly keeled; glumes (excluding any awns) exceeding the florets; culms (50)80-150 cm tall	M. emersleyi
66. Basal sheaths rounded; glumes (excluding any awns) exceeded by the florets; culms 30-160 cm tall.	→ 67
67. Glumes apices puberulent or scabridulous, acuminate to acute; lemmas long-acuminate, the demarcation of the lemma body and awn not evident	M. elongata
67. Glume apices glabrous or sparsely hirtellous, obtuse to acute, sometimes awned; lemmas acute to acuminate, the demarcation of the lemma body and awn evident.	→ 68
68. Glumes neither awned nor mucronate; spikelets dark purple; lemmas scabrous distally.	→ 69
69. Panicles 8-41 cm wide, open, diffuse, the branches strongly divergent; pedicels 10-40(50) mm long; in the Flora region, restricted to the eastern United States, growing from Connecticut south to Kansas, Oklahoma, eastern Texas, and Florida	M. capillaris
69. Panicles 2-5 (12) cm wide, loosely contracted to open, most branches appressed to ascending, occasionally a few diverging up to 80°; pedicels 1-10 mm long; in the Flora region, restricted to the southwestern United States, growing from Arizona to western Texas	M. rigida
68. Glumes usually awn-tipped or mucronate; spikelets stramineous, brown, or purplish; lemmas smooth or scabrous distally.	→ 70
70. Lemmas shiny, smooth; blades tightly involute, 0.2-1.2 mm wide; panicles 2-5 cm wide, loosely contracted; branches diverging up to 70° from the rachises	M. setifolia
70. Lemmas not shiny, usually scabrous, at least distally; blades flat or involute, 1-4 mm wide; panicles 5-40 cm wide, loosely contracted to open; branches diverging 30°-100° from the rachises.	→ 71
71. Panicles 10-20(30) cm long, about equally wide, not diffuse; branches spreading up to 80° from the rachises at maturity; spikelets stramineous, brownish or purple-tinged; lemmas awned, the awns 0.5-6 mm long	M. reverchonii
71. Panicles 15-50(60) cm long, narrower than long, diffuse; branches spreading 30-100° from the rachises at maturity; spikelets usually purplish; lemmas unawned or, if awned, the awns to 35 mm long.	→ 72
72. Upper glumes unawned or with awns to 5 mm long; lemmas without setaceous teeth or the teeth no more than 1 mm long; lemma awns 2-13(18) mm long	M. capillaris
72. Upper glumes awned, the awns 2-25 mm long; lemmas with setaceous teeth 1-5 mm long; lemma awns 8-35 mm long	M. sericea
54. Panicles narrow, 0.2-3(5) cm wide; branches appressed to ascending at maturity, usually spikelet-bearing their whole length [for opposite lead, see p. 150].	→ 73
73. Panicles spikelike, 0.1-1.2 cm wide, sometimes interrupted near the base; branches appressed, 0.3-1.2(4) cm long.	→ 74
74. Culms 3-20(35) cm tall, often decumbent and rooting at the lower nodes; blades 1-4(6) cm long	M. filiformis
74. Culms (15)20-150 cm tall, stiffly erect, not rooting at the lower nodes; blades 1.4-50 cm long, at least some more than 6 cm long.	→ 75
75. Lemmas awned, awns 3-10 mm long; lemmas scabridulous, the veins and margins glabrous	M. palmeri
75. Lemmas unawned, sometimes mucronate, the mucros up to 1 mm long; lemmas with hairs on the lower 1/6, the hairs sometimes extending to 3/4 of the lemma length over the midvein and margins.	→ 76
76. Basal leaf sheaths rounded on the back; panicles 15-60 cm long	M. rigens
76. Basal leaf sheaths compressed, the backs keeled; panicles 4-16 cm long.	→ 77
77. Ligules 0.2-0.8 mm long; paleas glabrous; glume apices gradually acute to acuminate, mucronate, the mucros to 0.3 mm long	M. cuspidata
77. Ligules 1-3(5) mm long; paleas pubescent between the veins; glumes abruptly narrowed, acute or obtuse, awned, the awns 0.5-1 mm long	M. wrightii
73. Panicles not spikelike, 0.6-5 cm wide; branches appressed, ascending, or diverging up to 70°, 0.2-13 cm long.	→ 78
78. Ligules 10-35 mm long, firm and brown basally, membranous distally; glumes as long as or longer than the florets.	→ 79
79. Basal sheaths rounded; lemmas unawned or with awns to 2 mm long; plants of Arizona and New Mexico	M. longiligula
79. Basal sheaths compressed-keeled, at least basally; lemmas unawned or with awns to 4 mm long; endemic to south central Texas, sometimes grown as an ornamental	M. lindheimeri
78. Ligules 0.2-10 mm long, usually membranous throughout, sometimes firmer basally, never brownish; glumes shorter than the florets.	→ 80
80. Lemma awns 0.5-6 mm long.	→ 81
81. Blades 10-60 cm long.	→ 82
82. Glumes acute, unawned; ligules 4-10 mm long, acute, lacerate; spikelets grayish-green	M. dubia
82. Glumes acute to acuminate, awned, the awns to 1.5 mm long; ligules 1-3 mm long, truncate, ciliolate; spikelets yellowish-brown to purplish	M. palmeri
81. Blades to 10 cm long.	→ 83
83. Glumes 2-4 mm long; lemmas 3.5-5 mm long, the awns flexuous; ligules 1-2 mm long, with lateral lobes less than 1.5 mm longer than the central portion; anthers 1.3-3 mm long, purple	M. arsenei
83. Glumes less than 2 mm long; lemmas 1.8-3(3.4) mm long, the awns straight; ligules 0.2-1.1 mm long, without lateral lobes; anthers 0.2-0.9 mm long, yellow.	→ 84
84. Upper glumes veinless, 0.1-0.3 mm long; lower glumes rudimentary or lacking, veinless	M. schreberi
84. Upper glumes 1(2)-veined, 0.8-1.9 mm long; lower glumes 0.4-1.5 mm long, veinless or 1-veined	M. ×curtisetosa
80. Lemma awns 6-40 mm long.	→ 85
85. Glumes 0.3-1 mm long, obtuse to acute, sometimes erose, not awned; anthers 0.9-1.6 mm long	M. spiciformis
85. Glumes (1)1.2-3.5 mm long, acute to acuminate, usually awn-tipped; anthers 0.9-3 mm long.	→ 86
86. Blades 15-50 cm long; lemma awns 3-10 mm long; plants of southern Arizona and Chihuahua, Mexico	M. palmeri
86. Blades 1-15 cm long; lemma awns 4-30 mm long; plants of the southwestern United States, including southern Arizona.	→ 87
87. Lemmas and paleas almost glabrous, with only a few short hairs on the calluses; ligules with lateral lobes, the lobes 1.5-3 mm longer than the central portion; culms erect and plants tightly cespitose at the base; sheaths and blades usually with dark brown necrotic spots	M. pauciflora
87. Lemmas and paleas pubescent on the lower 1/3 – 2/3 of the midveins and margins; ligules without lateral lobes or with lobes less than 1.5 mm longer than the central portion; culms decumbent and plants loosely cespitose; sheaths and blades without necrotic spots.	→ 88
88. Anthers 0.9-1.5 mm long, yellowish; panicles usually 7-20 cm long	M. tenuifolia
88. Anthers 1.3-2 mm long, purplish or orange; panicles 2-13 cm long.	→ 89
89. Anthers orange, 1.5-2 mm long; lemmas elliptic, 2-3.5 mm long, with awns 10-20(25) mm long; panicles 0.3-1.8 cm wide	M. polycaulis
89. Anthers purple, 1.3-3 mm long; lemmas lanceolate, 3.5-5 mm long, with awns 4-12(20) mm long; panicles 1-5 cm wide	M. arsenei

Flora of North America species comparison

Muhlenbergia

Muhlenbergia pectinata

Muhlenbergia

Muhlenbergia pectinata