COMPAEATIYE ANALYSIS. 



237 



AvENA. — Florets with two long bristles at summit 

 Plorets without bristles at summit 



Ctnostjetjs. — Outer palea terminating in a short awn, not 

 half length of palea 

 Outer palea terminating in a long awn, as 

 long as the palea 



PoA. — Florets webbed . " . 



Florets not webbed 



1. Upper leaf much longer than sheath 



Upper leaf about as long or longer than sheath 



2. Ligule of upper sheath short and rounded 

 Ligule of upper sheath long and pointed 



3. Ligule scarcely perceptible, outer palea five-ribbed . 

 Ligule prominent, outer palea three-ribbed 



4. Florets hairy at base .... 

 Florets not hairy 



5. Outer palea three-ribbed 

 Outer palea five-ribbed 



6. Panicle erect, upper leaf Unear, folded 

 Panicle drooping, upper leaf lanceolate, flat 



7. Upper joiut situated above centre of stem 

 Upper joint situated below centre of stem 



8. Second sheath not reaching to first joint . 

 Second sheath extending beyond first joint 



9. Small glume reaching beyond base of third floret 

 Small glume not reaching beyond base of second floret 



10. Eachis and branches rough 

 Eachis and branches smooth 



11. Eachis and branches rough to touch . 

 Eachis and branches smooth to touch 



12. Glumes with a prominent lateral rib on each side 

 Glumes without lateral ribs ... 



13. Lower half of central rib of outer palea smooth 

 Central rib of outer palea rough the whole length . 



14. Summit of upper glume reaching to base of third floret 

 Summit of upper glume reaching to base of fourth floret 



15. Outer palea three-ribbed 

 Outer palea seven-ribbed 



16. Panicle compound, spikelets not a quarter of an inch in 



Strigosa. 

 Fatua. 



Cristatus. 



JScTiinatus. 



1 



4 

 2 

 3 



Pratensis. 

 . Trmalis. 

 Nemoralis. 

 Compressa. 



5 



. 12 



6 



. 7 



Laxa. 



9 



Polynoda. 

 Montana. 



10 



11 



Annua. 



length 



Panicle simple, spikelets an inch in length 



Maritima. 

 Procumbens. 

 13 

 . 14 

 15 



Rigida. 

 Loliacea. 

 Syhatica. 

 16 



Aquatica. 

 Fluitans. 



