238 



COIIPAEATIVE ANALYSIS. 



1. 



BucETOi. — Inflorescence racemed, approaching to a spike Loliaceum. 



Inflorescence panicled . . .1 



1. Panicle simple .... Pratense. 

 Panicle compound . . . .2 



2. Avrn considerably shorter than palea . . Elatius. 

 Awn considerably longer than palea . . Giganteum. 



Bromus. — Large glume seven-ribbed . . _ . 1 



Large glume three-ribbed . . .4 

 Summit of upper glume midway between its base and 



summit of third floret . . . .2 

 Summit of upper glume midway between its base and 



summit of second floret . . . .3 



Florets and glumes hairy . . . Mollis. 



Florets and glumes not hairy . . Eacemosus. 

 Twice width of outer palea considerably more than 



length of palea . . . Secalinus. 



Twice width of outer palea equal to length of palea Arvensis. 



Awns of florets much longer than calyx . . 5 



Awns of florets much shorter than calyx . . 6 



Spikelets drooping, awns longer than the florets . Sterilis. 



Spikelets erect, awns equal in length to the florets BianArus. 

 Lower floret about one-third longer than the small glume Erectus. 

 Lower floret about twice the length of the small glume Asjjer. 



Teisetdm. — Kadical leaves hairy 



Eadical leaves not haiiy 

 1. Ligule long and acute 



Ligule verj- short and obtuse 



pESircA. — Awns much longer than the florets 

 Awns much shorter than the florets 

 1. Pioot fibrous, stem under the panicle rough 

 Root creeping, stem under the panicle smooth 



TEiTictJii. — Spikelets long, on short footstalks 

 Spikelets short, without footstalks . 



1. Stem rough 

 Stem smooth 



2. Awns rather longer than the florets . 

 Awns very short, or wanting 



3. Eachis rough 

 Ptachis smooth 



Pratense. 

 Pichescens. 

 Flavescens. 



Bromoides. 



1 



Ovina. 

 Duriuscula. 



Sylvaticum. 



1 

 Cristatum. 

 2 

 Cariinum. 

 3 

 . Repens. 

 Junceum. 



LoLiuii. — Florets awned, glume longer than the spikelet Temulentum. 

 Florets not awned, glume shorter than the spikelet Perenne. 



