THE GRASSES OF MAINE. 15 



{ Outer glumes much shorter than the flowering glume, 

 SPOROBOLUS. 

 Outer glumes about the same length as the flowering glume, 

 AGROSTIS and SPOROBOLUS. 



1 o f Flowers with awns 14 



{ Flowers without awns 20 



1 M f Spikes solitary 15 



{ Spikes two or more ANDROPOGON. 



1 ,. f Spikes simple or nearly so 16 



( Spikes paniculate or lobed 18 



jg f Involucre of two or more bristles SETARIA. 



{ Involucre none 17 



T Flowering glumes with awns from one to three times their 



j- ( length ALOPECURUS. 



1 Flowering glumes with awns five times their length, 



[ HORDEUM. 



Flowers without awns HIEROCHLOA. 



Flowers with awns ... 19 



iq f Only the flowering glumes awned MUHLENBERGIA. 



\ Flowering glume and palea both awned .... ANTHOXANTHUM. 



2Q f Spikes terminal, cylindrical and solitary PHLEUM. 



"[ Spikes one-sided, several SPARTINA. 



21 f Flowers arranged in panicles 22 



( Flowers arranged in spikes 33 



22 f Flowers with awns 23 



{ Flowers without awns 28 



9 o f Flowering glume awned on the back 24 



{ Flowering glume awned from the end 27 



( Awn arises near the base of the flowering glume AIRA. 



24 j Awn arises above the middle of the back of the flowering 



( glume , , 25 



Awn arises near the middle and twisted TRISETUM. 



Awn arises at or near the apex, not twisted 26 



{Spikelets from three to six flowered (Plate 29) AVENA. 

 Spikelets from five to twelve flowered (Plate 22) . . .BROMUS. 



Awn twisted and arising from a cleft at the end of the flow- 

 ering glume DANTHONIA. 



Awn not twisted, arising from the end which is not cleft, 



FESTUCA. 



