34 



POACEAE. 



Lemma 5-ner\-ed or more. 

 Keels of the palea winged. 

 Keels of the palea not winged. 



Spikelets with the upper florets sterile and 



folded about each other. 

 Spikelets with the upper florets perfect, or 

 narrow and abortive. 

 Spikelets cordate: lemmas cordate at 



liase. 

 Spikelets not cordate; lemmas not cordate 

 at base. 

 Stigmas arising below the apex of the 



ovary. 

 Stigmas arising at the apex of the 

 ovar>'. 

 Lemmas compressed and keeled. 

 Lemma awn-pointed. 

 Lemmas pointless. 



Glumes 1-3-nerved. 

 Glumes 5-nerved or more. 

 Lemmas convex or rounded on the 

 back. 

 Lemmas acute or awned. 

 Lemmas obtuse and scarious at 

 apex. 

 Lemmas prominently 5-7- 



nerved 

 Lemmas obscurely 5-nerved. 



Tribe 



Chlorideae. 



75. Pleuropogon, 49. 



76. Melica, 49. 



77. Briza, 49. 



78. Bromus, 50. 



79. Dactylis, 52. 



80. PoA, 52. 



81. DiSTiCHLis, 56. 



82. Festuca, 56. 



83. Panicularia, 58. 



84. Puccinellia, 59. 



Spikelets not in digitate clusters. 



Spikelets much flattened; glumes unequal, keeled. 



Spikelets subterete; glumes equal, convex. 

 Spikelets in terminal digitate clusters. 



Spikelets i -flowered; stems creeping. 



Spikelets several-flowered; stems not creeping. 



85. Spartina, 60. 



86. Beckmannia, 60. 



87. Cynodon, 60. 



88. Eleusine, 61. 



LOLIUM, 61. 



Agropyron, 61. 



Tribe 8. Hordeae. 



Spikelets solitary at each joint of the rachis. 



Spikelets with one edge against the rachis; empty 



glume 1. 89 



Spikelets with their sides againsc the rachis; empty 

 glumes 2. 90 



Spikelets 2 to 4 at each notch of the rachis. 



Rachis not readily breaking into joints; spikelets 



1-7-flowered, 2-4 at each joint. 91. Elymus, 62 



Rachis readily breaking into joints. 



Spikelets i-flowered, three at each joint, only 



the central one perfect. 92 



Spikelets 1-5-flowered, 2-4 at each joint, all 

 perfect. 93 



47. ECHINOCHLOA. 



Coarse annuals with long leaves; spikelets 1-flowered, with 

 sometimes a staminate flower below, nearly sessile in panicled 



HORDEUM, 63. 

 SiTANION, 64. 



