232 



COMPAEATIVE ANALYSIS. 



Spikelets with one perfect floret 

 3. Leaves much shorter than the purplish panicle 

 Leaves much longer than the pale panicle 



(M. cserulea 



HoLcirs. 

 Awn longer than the calyx, joints of culm downy- 

 Awn not longer than the calyx, joints not downy 



AkKHEN ATHEEUil . 



Spikelets greenish brown 

 Florets awnless 

 Spike bluish, ovate 



Spikes alternate 



Setaeia. 

 Bristles of involucre, with reflexed teeth 

 Eristles of involucre, with erect teeth 



HlEllOOHLOS. 



Sesleeia. 

 Pasicum. 



Uniflora. 



. Ccerulea. 



Depauperata. 



B. Uooher.) 



. Mollis. 

 Lanatus. 



Avetiacemn. 



. Bo real is. 



. Cuirulea. 



Crus-galU. 



Verticillata. 

 Yiridis. 



Gltceeia, (Poa, Rooher.) 



L Florets with seven or more ribs. . . 2 



Florets with not more than five ribs . . 3 



2. Panicle much branched, plant four feet high . Aquatica. 

 Panicle slightly branched, plant not more than three feet 



high . . . . Fluitans. 



3. Panicle compact, rigid ... 4 

 Panicle spreading, not rigid . . .6 



4. Boot creeping .... Maritinia. 

 Boot fibrous . . . . .5 



5. Florets four or five, five-ribbed, plant procumbent . Procumbens. 

 Florets six or seven, nearly ribless, plant erect, or ascending Rirjida. 



6. Panicle reflexed in fruit . . . Distans. 

 Panicle not reflexed in fruit . . . Borreri. 



Poa. 



1 



Florets webbed . . . 



Florets not webbed 



2. Stem bulbous at base 

 Stems not bulbous at base . 



3. Culm much compressed, spikelets five or more flowered 

 Culm round, or but little compressed, spikelets three 



four-flowered .... 



7 

 Bullosa. 

 3 

 Compressa. 

 )r 



4 



