146. Graminkae 327 



8. Lemma without a tuft of hairs at the base. 



10. Lemma awnless or with a dorsal awn 38. Agrostis 



10. Lemma with a terminal awn, or mucronatc at apex 



42. Muhlenbergia 



6. Grain not permanently enclosed in the lemma and palet, readily 



separating from the pericarp 43. Sporobolus 



1. Lemma indurated when mature, closely enveloping the grain. 



11. Lemma awnless 46. Milium 



1 1. Lemma awned. 



12. Lemma 3-awned 49. Arixtida 



12. Lemma 1-awned. 



13. Awn twisted or bent 48. Stipa 



13. Awn not twisted or bent. 



14. Lemma broad, the awn deciduous 47. Oryzopsis 



14. Lemma narrow, the tip awned or mucronate. 



15. Rachilla not prolonged behind the palet 



42. Muhlenbergia 



\^. Rachilla prolonged into a bristle behind the palet 



45. Brachyelytrum 



Tribe 6. Chlorideae. — Grama Tribe 



1. Plants monoecious or dioecious 50. Buchloe 



1. Plants with perfect flowers. 



2. Spikelets with more than 1 perfect floret; plants annual. 



3. Spikes numerous, slender, racemose 54. Leptochloa 



3. Spikes few, digitate. 



4. Rachilla prolonged beyond the spikelets 52. Dactyloctenium 



4. Rachilla not prolonged 51. Eleusine 



2. Spikelets with only one perfect floret. 



5. Spikelets with one or more modified florets above the perfect one. 



6. Spikes digitate 58. Chloris 



6. Spikes racemose 59. Bouteloua 



5. Spikelets without additional modified florets. 



7. Spikelets falling entire, the rachilla articulated below the glumes. 



8. Spikelets narrow; glumes unequal 57. Spartina 



8. Spikelets globose; glumes equal 56. Beckmannia 



7. Spikelets with the rachilla articulated above the glumes, these there- 

 fore persistent. 



9. Spikes digitate 53. Cynodon 



9. Spikes racemose 55. Schedonnardus 



Tribe 7. Phalarideae. — Canary Grass Tribe 



1. First and second lemmas oval. 



2. Glumes nearly equal; lower florets staniinate; spikelets brown, glossy 



60. Hierochloe 



2. Glumes very unequal; lower florets consisting of sterile lemmas 



61. Anthoxanthum 



1. First and second lemmas bristle-like 62. Phalaris 



Tribe 8. Oryzeae. — Rice Tribe 



1. Spikelets perfect; stamens 1-3 63. Leersia 



1. Spikelets unisexual; stamens 6 64. Zizania 



