234 



COMPAEATIVE ANALYSIS. 



11. Panicle mucli branched, root creeping 

 Panicle not mucli branched, root fibrous 



Bkomus. 



1. Stamens two 

 Stamens three 



2. Leaves aurioled, glabrous 



Leaves not auricled, mostly pubescent 



3. Awn much longer than florets . 

 Awn not much longer than florets 



JElatior. 

 Pratensis. 



Biandrus. 

 2 



Giganteus. 

 3 

 4 

 5 



4. Panicle erect in flower, awn twice as long as the florets Maximus. 

 Panicle drooping, awn not twice as long as the florets 



5. Florets pubescent .... 

 Florets glabrous .... 



6. Florets about eight, remote, and longer than the awn 

 Florets nine or more, crowded, as long as the awn 



7. Leaves slightly hairy, panicle spreading 

 Leaves very pubescent, panicle erect, close 



8. Panicle drooping in fruit 

 Panicle erect .... 



9. Spikelets lanceolate, awns straight 

 Spikelets ovate, awns not straight 



10. Awns remarkably spreading, leaves pubescent 

 Awns not spreading, leaves slightly hairy 



11. Eoot leaves much narrower than the oauline 

 Root leaves not narrower than the cauline 



AVENA. 



1. Spikelets drooping, florets not longer than the calyx 

 Spikelets erect, florets mostly longer than the calyx 



2. Florets terminated by two bristles 

 Florets not terminated by two bristles 



3. Glumes very unequal .... 

 Glumes nearly equal 



4. Leaves downy, spikelets two or three-flowered 

 Leaves not downy, spikelets more than three-flowered 



5. Lower leaves involute 



Leaves flat .... 



6. Sheaths flat, lower part of culm two-edged 

 Sheaths round, culm round 



AEirNDO. 



Florets purplish, culm five feet high 



Eltmus. 

 1. Leaves flat, florets awned 



Sterilis. 

 6 

 8 

 Asper. 

 7 

 Velutinus. 

 Mollis. 

 9 

 11 

 Arvensis. 

 10 

 Squarrosum. 

 SeoaUnus. 

 ^rectus. 

 Racemosus- 



2 

 3 



Fatua. 

 Flavescens. 

 4 



5 



Pratensis. 

 6 



. Alpina. 



Phragmites. 



Huropaus. 



