270 OHIO BIOLOGICAL SURVEY 



•V-'. Inflorescence not monecious. altho the plants may be diecious. 53 



52. .Monecious, the staminate and carpellate spikelets in different parts of the 

 same inflorescence or on different inflorescences; stem solid. 72 



53. Spikelets in a simple terminal spike. 54 



.">:;. Spikelets usually on one side of digitate or racemose branches of the in- 

 florescence, til 



54. Spikelets solitary at each node of the rachis. 55. 



54. Spikelets 2-several at each node of the rachis. 58. 



55. Spikelets with their hacks turned to the rachis. Lolium. (22) 



55. Spikelets with their sides turned to the rachis. 56 



56. Palet adherent to the grain; wild perennial grasses. Agropyron. (23) 



56. Palet free from the grain; ours cultivated or escaped annuals. 57 



57. Spikelets usually 3-several-flowered. Triticum. (24) 



57. Spikelets 2-flowered. Secale. (25) 



58. Spikelets 2-several-flowered. 59 



58. Spikelets 1 -flowered, sometimes with the vestige of a second flower, usually 

 in threes at the joints of the rachis, some of the spikelets often vestigial. 



Hordcum. (28) 



59. Rachis of the spike jointed and readily breaking up at maturity. Sitanion. 



59. Rachis not breaking up at maturity. 60 



60. Spikes mostly dense; empty glumes a little smaller than the flowering glumes. 



Ely tints. (26) 

 CO. Spikes very loose; empty glumes very small or none. Hystrix. (27) 



61. Joints of the rachis or rachilla with prominent hairs; stem solid; spikelets 

 in pairs, 1 stalked and 1 sessile. 62 



61. Joints of the rachis or rachilla not with hairs, at most only short pubescent. 63 



62. Spikelets all perfect. Miscanthus. (64) 

 6:2. Sessile spikelets perfect, the pedicellate staminate or sterile and vestigial. 



Andropogon. (65) 



63. Spikelets oval, articulated below the empty glumes, compact in form. 64 



63. Spikelets lanceolate, articulated above the empty glumes, except in Spartina ; 

 flowering glumes with awns or points. 68. 



64. Inflorescence with prominently digitate branches or simple. 65 



64. [nflorescence branches racemose. 66 



65. Lemma with inrolled margins, not hyaline; spikelets oblong to orbicular. 



Paspalum. (57) 



65. Lemma with hyaline margins, not inrolled; spikelets lanceolate. 



Syntherisnta. ( 55 ) 

 fiii. Spikelets dorsally compressed: stems solid or with delicate pith. 



Echinochloa. (56) 



66. Spikelets laterally compressed. (57 



67. Spikelets near the ends of long stalked branches of a spreading panicle. 



Homalocenchrus, (60) 



67. Spikelets in two rows on the erect branches of the panicle, the branches 

 sessile. Beckmannia. (30) 



68. [nflorescence with numerous short reflexed branches. Atheropogon, (33) 



68. [nflorescence with few spreading or ascending branches or with numerous 

 digitate branches. 69 



69. [nflorescence branches digitate. 70 

 ''»!). [nflorescence branches racemose. 71. 



To. Spikelets L-flowered; plants extensively creeping. Capriola. (31) 



70. Solkelets with 2-several perfect flowers, stems tufted. Eleusine. (32) 



