COMPARATIVE ANALYSIS. 



235 



Leaves involute, florets awnless . . .2 



2. Spike drooping, glumes longer than the florets . Geniculatus. 



Spike erect, glumes not longer than the florets Arenarius. 



HORDEDM. 



1. Glumes all setaceous .... Pratensc. 

 Glumes not all setaceous . . . .2 



2. Glumes of lateral florets setaceous, of central floret lanceolate Murinum. 

 Inner glumes of lateral florets not setaceous, the rest 



setaceous .... Maritimum. 



TRincm. 



1. Spikelets unilateral . . . Luliaccum. 

 Spikelets distichous .... 2 



2. Glumes and florets obtuse, leaves involute . . Junccum. 

 Glumes and florets awned or pointed, leaves flat . 3 



3. Glumes scarcely ribbed, spikelets crowded . Cridatum. 

 Glumes ribbed, spikelets not crowded . . 4 



4. Eoot fibrous ..... Caninum. 

 Eoot creeping .... Repem. 



BEACFITrODID^r. 



Spike drooping, awns longer than the florets . Syhaticum. 



Spike erect, awns shorter than the florets . . Pinnatum. 



Lolium. 



1. Spikelets much longer than the calyx . . Percnne. 

 Spikelets not longer than the calyx . . 2 



2. Florets with long rigid awns . . Temulentum. 

 Florets with short soft awns . . . Arvense. 



HoTTBffiLLIA. 



Glumes united .... Incurvata. 



Knappia. 



Root fibrous, florets very hairy . . . Agrostidca. 



Spartina. 

 Florets very hairy ..... Stricta. 



Florets glabrous ..... Alterniflora. 



Cymodon. 



Florets glabrous, longer than the glumes . Dactylon. 



Digitaria. 



Leaves pubescent .... Sangm'nalis. 



Leaves glabrous .... -Humifusa. 



2 M 



