Genera. 

 10. 



16. 



BUCETUM. 



Bromus. 



ANALYTICAL ARRANGEMENT 



Species. 



{ Rachis and branches rough Poa ccesia. 



\ Rachis and branches smooth Poa annua. 



\ Rachis and branches rough to the touch Poa distans. 



\ Rachis and branches smooth to the touch Poa mantima. 



( Glumes with a prominent lateral rib on each 



^ side Poa procwnbens. 



( Glumes without lateral ribs 13. 



! Lower half of the central rib of outer palea, 

 smooth 14. 

 Central rib of outer palea rough the whole length. 1 5. 



{Summit of the upper glume reaching to the base 

 of the third floret Poa rigida. 

 Summit of the upper glume reaching to the base 

 of the foiu-th floret Poa loliacea. 



^ Outer palea three-ribbed Poa sylvatka. 



( Outer palea seven-ribbed 16. 



C Panicle compound. Spikelets not exceeding a 



j quarter of an inch in length Poa aquatica. 



I Panicle simple. Spikelets usually an inch in 



I length Poafluitans. 



\ Inflorescence racemed, approaching to a spike.Bucetum loliaceum 

 { Inflorescence panicled 1. 



( Panicle simple Bucetum pratense. 



\ Panicle compound 2. 



{ Awn considerably shorter than the palea Bucetum elatius. 



i Avra much longer than the palea Bucetum giganteum. 



\ Large glume seven-ribbed 1. 



< Large glume three-ribbed 4. 



( Summit of the upper glume midway between its 



J base and summit of the third floret 2. 



I Summit of the upper glume midway between its 

 L base and summit of the second floret 3. 



( Florets and glumes hairy Bromus mollis. 



\ Florets and glumes not hairy Bronim racemosus. 



Plate 

 40 

 40 



41 

 42 



