1. Inflorescences clearly exceeded by the upper leaves, often completely or almost completely enclosed in the upper leaf sheaths; culms 1-30(75) cm tall. | → 2 |
2. Lemmas 3-lobed, the lobes ciliate; spikelets with 4 florets | Blepharidachne |
2. Lemmas not 3-lobed or the lobes not ciliate; spikelets with 1-60 florets. | → 3 |
3. Spikelets (and often the plants) unisexual. | → 4 |
4. Leaves strongly distichous; lemmas 9-11-veined; plants unisexual, growing in saline and alkaline soils. | → 5 |
5. Pistillate and staminate inflorescences consisting of a single spikelet | Monanthochloë |
5. Pistillate and staminate inflorescences consisting of more than 1 spikelet | Distichlis |
4. Leaves not strongly distichous; lemmas 1-5-veined; plants unisexual or, if bisexual, with separate pistillate and staminate inflorescences, growing in a variety of soils. | → 6 |
6. Spikelets 5-26 mm long; pistillate and staminate inflorescences similar, simple panicles; glumes and lemmas unawned, mucronate, or 1-awned | Eragrostis |
6. Spikelets 2.5-7 mm long; pistillate and staminate inflorescences strongly dimorphic; staminate inflorescences with pectinate, spikelike branches; pistillate spikelets with conspicuously 3-awned glumes or distal florets. | → 7 |
7. Upper glumes of the pistillate spikelets white, rigid, globose structures termin¬ating in 3 awnlike teeth; pistillate spikelets with 1 floret, without rudimentary florets, the floret unawned or shortly 3-awned; staminate spikelets 4-6 mm long; anthers 2.5-3 mm long, brownish, red, or orange; widespread species of the central plains | Buchloë |
7. Upper glumes of the pistillate spikelets membranous, unawned; pistillate spikelets with one 3-awned floret and a distal 3-awned rudiment; staminate spikelets 3-4 mm long; anthers 2-2.5 mm long, pale; known, within the Flora region, only from Florida | Opizia |
3. Spikelets bisexual, usually at least the lowest floret in each spikelet bisexual, in Dasyochloa the third floret in each spikelet bisexual or pistillate, if pistillate, the lowest 2 florets staminate. | → 8 |
8. Lemma margins with a tuft of hairs at midlength, glabrous elsewhere; blades with white, thickened margins and sharply pointed | Munroa |
8. Lemma margins glabrous, or with hairs but the hairs not forming a tuft at midlength; blades without white cartilaginous margins, not sharply pointed. | → 9 |
9. Lemmas awned, the awns 1-11 mm long. | → 10 |
10. Plants stoloniferous; inflorescences 1-2.5 cm long, dense panicles; lemmas bilobed, the lobes about 1/2 as long as the lemmas; ligules of hairs | Dasyochloa |
10. Plants not stoloniferous; inflorescences 1.5-76 cm long, not dense; lemmas entire or minutely bilobed; ligules membranous, sometimes ciliate | Leptochloa |
9. Lemmas unawned, sometimes mucronate, with mucros less than 1 mm long. | → 11 |
11. Spikelets with 2-20 florets; inflorescences panicles of 2-120 spikelike branches | Leptochloa |
11. Spikelets with 1(3) florets; inflorescences simple panicles, often highly contracted, without spikelike branches. | → 12 |
12. Inflorescences 0.3-7.5 cm long, dense, spikelike or capitate panicles 1-8 times longer than wide; glumes strongly keeled; plants annual | Crypsis |
12. Inflorescences 1-60 cm long, sometimes dense and spikelike but, if less than 8 cm long, more than 8 times longer than wide; glumes rounded or weakly keeled; plants annual or perennial | Sporobolus |
1. Inflorescences usually equaling or exceeding the upper leaves; culms 1-500 cm tall. | → 13 |
13. Inflorescences with disarticulating branches, disarticulation at the base of the branches or (in Lycurus) the fused pedicels; branches 0.04-7 cm long, often globose or spikelike (fused to the rachis and not evident in Lycurus), usually with fewer than 15 spikelets per branch. | → 14 |
14. Upper glumes with straight or uncinate spinelike projections; spikelets crowded, the branches condensed into burs | Tragus |
14. Upper glumes without spinelike projections; spikelets sometimes crowded, but not forming bur like clusters. | → 15 |
15. Branches not fused to the rachises; spikelets more than 3 per branch, usually all alike, sometimes the proximal spikelet sterile or replaced with short secondary branches. | → 16 |
16. Both glumes much longer than the florets, usually exceeding the distal florets; plants annual | Dinebra |
16. Lower glumes shorter than or subequal to the lower florets, 1 or both glumes usually exceeded by the distal florets; plants usually perennial. | → 17 |
17. Spikelets with 1-2(3) florets; branches disarticulating promptly, before the spikelets disarticulate | Bouteloua |
17. Spikelets with 2-8 florets; branches disarticulating tardily, initially the spikelets disarticulating above the glumes | Pogonarthria |
15. Branches sometimes fused to the rachises; spikelets 1-3 per branch, usually some spikelets on each branch sterile or staminate and 1 pistillate or bisexual. | → 18 |
18. Axes of the branches extending beyond the base of the distal florets | Bouteloua |
18. Axes of the branches terminating at the base of the distal spikelet. | → 19 |
19. Spikelets in pairs; glumes awned, the lower glumes (1)2(3)-awned, the upper glumes 1-awned; panicle branches often fused to the rachises | Lycurus |
19. Spikelets in triplets; glumes unawned, 1-awned, or 3-awned; panicle branches sometimes appressed, but not fused, to the rachises. | → 20 |
20. Branches straight at the base; central spikelets sessile | Hilaria |
20. Branches sharply curved at the base; central spikelets sessile or pedicellate. | → 21 |
21. Central spikelets with 1 bisexual floret; lateral spikelets with 1 floret, varying to rudimentary | Aegopogon |
21. Central spikelets with 3-4 florets, the lowest floret pistillate, bisexual, or staminate, the distal florets staminate or sterile; lateral spikelets usually with 2 florets | Cathestecum |
13. Inflorescences without disarticulating branches; branches, if present, often more than 4.5 cm long, variously shaped, including spikelike but not globose, often with more than 16 spikelets per branch. | → 22 |
22. Inflorescences spikes or racemes. | → 23 |
23. Spikelets with 1 bisexual or staminate floret and no additional florets. | → 24 |
24. Rachises falcate or curved; both glumes exceeding the florets | Microchloa |
24. Rachises straight; lower glumes exceeded by the florets, sometimes absent. | → 25 |
25. Spikelets solitary at each node; disarticulation below the glumes or the spikelets not disarticulating | Zoysia |
25. Spikelets paired, terminal on branches that are fused to the rachises; disarticulation at the base of the fused pedicel pairs | Lycurus |
23. Spikelets with more than 1 floret but sometimes only 1 floret bisexual, the additional florets sterile or staminate. | → 26 |
26. All spikelets unisexual, the functional florets either staminate or pistillate; plants either unisexual or with both pistillate and staminate spikelets. | → 27 |
27. Lemmas 9-11-veined; plants of saline habitats | Distichlis |
27. Lemmas 3-veined; plants of various habitats. | → 28 |
28. Lemmas of the pistillate florets with awns 3.4-6.8 mm long; branches of staminate inflorescences pectinate; staminate spikelets with 1 floret | Opizia |
28. Lemmas of the pistillate florets with awns 30-150 mm long; branches of staminate inflorescences not pectinate; staminate spikelets with 5-20 florets | Scleropogon |
26. Some or all spikelets bisexual, the florets bisexual or unisexual, but both staminate and pistillate florets present within an individual spikelet. | → 29 |
29. Lemmas of the pistillate or bisexual florets with awns 30-150 mm long; bisexual florets rarely found | Scleropogon |
29. Lemmas of the bisexual florets unawned or with awns less than 10 mm long; pistillate florets not present. | → 30 |
30. Inflorescences 5-15 cm long, apparently a pectinate spike, actually a solitary, pectinate, spikelike branch | Ctenium |
30. Inflorescences 1.5-10 cm long, spikes, spikelike racemes, or panicles, linear or densely cylindrical to ovoid. | → 31 |
31. Inflorescences linear, (1.5)4-10 cm long; rachises not concealed by the spikelets | Tripogon |
31. Inflorescences cylindrical to ovoid, 1.5-5 cm long; rachises concealed by the spikelets | Fingerhuthia |
22. Inflorescences simple panicles (sometimes highly condensed) or panicles of 1-120 spikelike branches. | → 32 |
32. Inflorescences simple panicles, sometimes highly contracted, even spikelike in appearance; spikelike branches not evident [for opposite lead, see p. 19]. | → 33 |
33. Spikelets usually with only 1 floret, occasionally with 2-3 florets. | → 34 |
34. Ligules membranous, hyaline, or coriaceous, sometimes ciliate; lemmas 3-veined (occasionally appearing 5-veined), usually awned, sometimes unawned or mucronate. | → 35 |
35. Lemmas and paleas densely sericeous over the veins and margins, glabrous between the veins | Blepharoneuron |
35. Lemmas and paleas glabrous to variously hairy but not densely sericeous over the veins and margins. | → 36 |
36. Lemmas usually awned or mucronate; spikelets usually with 1 floret | Muhlenbergia |
36. Lemmas unawned or mucronate; spikelets frequently with 2-3 florets | Eragrostis |
34. Ligules of hairs; lemmas 1(3)-veined, unawned, sometimes mucronate. | → 37 |
37. Panicles 0.3-4(7.5) cm long, 3-15 mm wide, spikelike or capitate, 1-8 times longer than wide; plants annual | Crypsis |
37. Panicles 1-80 cm long, 2-600 mm wide, dense to open, if less than 8 cm long, often 10 or more times longer than wide; plants annual or perennial. | → 38 |
38. Calluses usually glabrous or almost so; paleas glabrous; fruits falling free of the lemma and palea | Sporobolus |
38. Calluses evidently hairy, the hairs 1/4 - 7/8 as long as the lemmas; paleas hairy; fruits falling with the lemma and palea | Calamovilfa |
33. Spikelets with more than 1 floret. | → 39 |
39. Lemmas with (5)9-11 veins (the lateral veins obscure in Allolepis). | → 40 |
40. Spikelets unisexual; plants almost always unisexual, occasionally bisexual. | → 41 |
41. Lemmas 9-11-veined; glumes 2-7 veined; plants rhizomatous and/or stoloniferous, found in saline or alkaline soils | Distichlis |
41. Lemmas 1-6-veined; lower glumes of the staminate spikelets 1-veined, those of the pistillate spikelets 1-5-veined; plants stoloniferous or rooting at the lower nodes, not rhizomatous, not found in saline or alkaline soils. | → 42 |
42. Plants perennial, stoloniferous; paleas of the pistillate florets completely surrounding the ovaries, the intercostal region coriaceous | Allolepis |
42. Plants annual, rooting at the lower nodes; paleas of the pistillate florets not completely surrounding the ovaries, the intercostal region membranous or hyaline | Eragrostis |
40. All spikelets with at least 1 bisexual floret. | → 43 |
43. Glumes longer than the adjacent lemmas. | → 44 |
44. Glumes exceeded by the distal florets; spikelets with 3-7 bisexual florets plus reduced distal florets; lemmas of the bisexual florets 5-7-veined throughout | Swallenia |
44. Glumes exceeding the distal florets; spikelets with 2-4 florets, only the lowest floret bisexual; lemmas of the bisexual florets 3-veined basally, 5-7-veined distally | Fingerhuthia |
43. Glumes shorter than the adjacent lemmas. | → 45 |
45. Spikelets ovate-elliptical to ovate-triangular, 15-50 mm long, 6-16 mm wide; lower florets sterile, without paleas | Uniola |
45. Spikelets usually elliptical to lanceolate, 1-26 mm long, 0.6-9 mm wide; lower florets in each spikelet bisexual, with paleas. | → 46 |
46. Calluses glabrous or sparsely pubescent; lemmas (1)3(5)-veined; spikelets 1-26 mm long, 0.6-9 mm wide | Eragrostis |
46. Calluses densely pubescent; lemmas 5-, 7-, or 9-veined; spikelets 10-16 mm long, 2.5-5 mm wide | Vaseyochloa |
39. Lemmas with 1-3 veins (occasionally with scabrous lines that may be mistaken for additional veins). | → 47 |
| → 48 |
48. Staminate and pistillate florets strongly dimorphic; plants unisexual or bisexual, bisexual plants with unisexual or bisexual spikelets; pistillate spikelets with 3-5 functional florets and lemma awns (30)50-150 mm long; staminate spikelets with 5-10(20) florets and unawned or shortly awned (to 3 mm) lemmas | Scleropogon |
48. Staminate and pistillate florets similar; plants unisexual; spikelets with 4-60 florets, all or almost all functional; lemmas 1.5-10.5 mm, unawned, sometimes mucronate. | → 49 |
49. Plants perennial, stoloniferous; paleas of the pistillate florets completely surrounding the ovaries, the intercostal region coriaceous | Allolepis |
49. Plants annual, rooting at the lower nodes; paleas of the pistillate florets not completely surrounding the ovaries, the intercostal region membranous or hyaline | Eragrostis |
47. At least 1 floret in each spikelet bisexual. | → 50 |
50. Lemmas, including the calluses, glabrous or inconspicuously hairy; lemma apices usually entire, sometimes minutely toothed. | → 51 |
51. Spikelets with (1)2-60 florets; lemmas unawned, sometimes mucronate; ligules usually membranous and ciliate or ciliolate, sometimes of hairs | Eragrostis |
51. Spikelets with 1(2-3) florets; lemmas often awned, sometimes unawned or mucronate; ligules membranous, sometimes ciliolate, not ciliate | Muhlenbergia |
50. Lemma bodies conspicuously hairy over the veins and/or calluses conspicuously hairy; lemma apices usually with emarginate, bilobed, or trilobed apices, sometimes entire. | → 52 |
52. Leaf margins evidently cartilaginous | Erioneuron |
52. Leaf margins not cartilaginous. | → 53 |
53. Palea keels long hairy distally, the distal hairs 0.5-2 mm long | Triplasis |
53. Palea keels glabrous or with hairs less than 0.5 mm long. | → 54 |
54. Lemmas unawned, the midveins sometimes excurrent up to 0.5 mm. | → 55 |
55. Lemmas rounded to truncate, emarginate to bilobed; all 3 lemma veins often pilose basally | Tridens |
55. Lemmas acute, entire or with 3 minute teeth, glabrous or shortly pubescent on the distal 2/3, the pubescence not confined to the veins | Redfieldia |
54. Lemmas awned, the awns 1-7 mm long. | → 56 |
56. Plants 80-500 cm tall; panicles 35-73 cm long, plumose; lemma margins pilose; lemma apices bifid, awned from between the teeth; awns about 3 mm long | Neyraudia |
56. Plants to 2-90 cm tall; panicles 6-30 cm long, not plumose; lemma margins sparsely pilose; lemma apices 3-4-lobed or -toothed and 3-awned; central awns 5-7 mm long, lateral awns 6-7 mm long | Triraphis |
32. Inflorescences panicles of spikelike branches, the branches digitately or racemosely arranged on the rachises [for opposite lead, see p. 18]. | → 57 |
57. Inflorescence branches 1 or more, if more than 1, arranged in terminal, digitate clusters, sometimes with additional branches or whorls below the terminal cluster. | → 58 |
58. Inflorescences with 1(2) falcate branches. | → 59 |
59. Spikelets with 2 well-developed sterile or staminate florets below the bisexual florets; additional sterile or staminate florets present distal to the bisexual floret | Ctenium |
59. Spikelets usually with 1, rarely 2, florets, the lowest or only floret bisexual | Microchloa |
58. Inflorescences with more than 1 branch or, if only 1, the branch not strongly falcate. | → 60 |
| → 61 |
61. Staminate spikelets 4-6 mm long, with 2 florets; upper glumes of the pistillate spikelets indurate, white | Buchloë |
61. Staminate spikelets 3-4 mm long, with 2 florets; upper glumes of the pistillate spikelets membranous | Opizia |
60. Plants bisexual, all spikelets with at least 1 bisexual floret. | → 62 |
62. Spikelets with more than 1 bisexual floret. | → 63 |
63. Panicle branches 0.4-7 cm long, terminating in a point | Dactyloctenium |
63. Panicle branches 1-22 cm long, terminating in a functional or rudimentary spikelet. | → 64 |
64. Disarticulation eventually below the glumes, initially below the lemmas and caryopses, the paleas persistent; panicle branches terminating in a rudimentary spikelet | Acrachne |
64. Disarticulation above the glumes, usually also below the florets; panicle branches terminating in a functional spikelet. | → 65 |
65. Lemmas 3-awned, the central awns 8-12 mm long | Trichloris |
| → 66 |
66. Lemmas usually with hairs over the veins, at least basally, the apices often toothed, sometimes mucronate or awned | Leptochloa |
66. Lemmas glabrous, the apices entire, neither mucronate nor awned | Eleusine |
62. Spikelets usually with only 1 bisexual floret (occasionally 2 in some genera), often with additional staminate, sterile, or modified florets. | → 67 |
67. Spikelets usually without sterile or modified florets; lemmas unawned | Cynodon |
67. Spikelets with 1 or more sterile florets distal to the bisexual floret; lemmas of the bisexual florets often awned. | → 68 |
68. Lowest lemmas in the spikelets 3-awned, the central awns 8-12 mm long, the lateral awns 0.5-12 mm long | Tricbloris |
68. Lowest lemmas in the spikelets usually unawned or with a single awn, if 3-awned, the lateral awns less than 0.5 mm long. | → 69 |
69. Spikelets dorsally compressed | Enteropogon |
69. Spikelets laterally compressed or terete. | → 70 |
70. Upper glumes truncate or bilobed; lowest lemmas unawned or with an awn to 1.2 mm long | Eustachys |
70. Upper glumes acute to acuminate; lowest lemmas usually awned, the awns to 37 mm long | Chloris |
57. Inflorescence branches more than 1, racemosely arranged on the rachises. | → 71 |
71. All spikelets unisexual. | → 72 |
72. Staminate spikelets 4-6 mm long, the anthers 2.5-3 mm long; pistillate spikelets with 1 unawned or shortly awned floret; wide spread species of the central plains | Buchloë |
72. Staminate spikelets 3-4 mm long, the anthers 2-2.5 mm long; pistillate lemmas with awns 3.4-6.8 mm long; in the Flora region, known only as an occasional escape from lawns and experimental plots in Florida | Opizia |
71. All spikelets with at least 1 bisexual floret. | → 73 |
73. Inflorescence branches woody, terminating in hard, sharp points | Cladoraphis |
73. Inflorescence branches not particularly stiff or rigid, terminating in spikelets or points. | → 74 |
74. Spikelets with more than 1 bisexual floret, sometimes also with reduced florets. | → 75 |
75. Lemmas 7-11-veined, mucronate, the mucros 0.1-0.3 mm long; not established in the Flora region | Aeluropus |
75. Lemmas 3-veined, unawned, mucronate, or awned, the awns often much more than 1 mm long; established in the Flora region. | → 76 |
76. Lower glumes exceeding the lowest lemmas, sometimes exceeding the distal lemmas | Trichoneura |
76. Lower glumes not or only slightly exceeding the lowest lemmas. | → 77 |
77. Inflorescences with 50 or more closely spaced, arcuate, tardily deciduous branches | Pogonarthria |
77. Inflorescences with 2-120 straight, non-disarticulating branches. | → 78 |
78. Spikelets with (2)3-12(20) bisexual florets | Leptochloa |
78. Spikelets with 2-4 florets, but only the lowest 1(2) florets bisexual | Gymnopogon |
74. Spikelets with 1 bisexual floret, sometimes with sterile, rudimentary, or modified florets distal to the bisexual floret. | → 79 |
79. Functional spikelets with sterile, rudimentary, or modified florets distal to the bisexual floret. | → 80 |
80. Spikelets widely spaced to slightly imbricate, appressed to the branch axes | Gymnopogon |
80. Spikelets densely imbricate, varying from appressed to strongly divergent. | → 81 |
81. Inflorescence branches usually solitary at each node (sometimes only 1 per panicle); spikelets laterally compressed or terete | Bouteloua |
81. Inflorescence branches usually more than 1 at the lower nodes; spikelets dorsally compressed | Enteropogon |
79. Functional spikelets with only 1 floret, lacking sterile, rudimentary, or modified florets. | → 82 |
82. Spikelets distant to slightly imbricate, appressed to the branches; branches strongly divergent. | → 83 |
83. Blades with thick, white margins and a well-developed midrib | Schedonnardus |
83. Blades lacking both thick, white margins and well-developed midribs | Gymnopogon |
82. Spikelets clearly imbricate, appressed to strongly divergent; branches appressed to strongly divergent. | → 84 |
84. Spikelets laterally compressed, appressed to divergent | Spartina |
84. Spikelets dorsally compressed, appressed | Willkommia |