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COMPARATIVE ANALYSIS. 



2. 

 3. 



4. 



5. 



6. 



7. 



8. 



9. 

 10. 

 11. 

 12. 

 13. 

 14. 

 15. 

 16. 

 17. 

 18. 

 19. 

 20. 

 21. 

 22. 

 23. 



Flowers in unilateral spikes . . .3 



Flowers not unilateral ... 6 



Calyx many-flowered . . . Tritioum. 



Calyx one or two-flowered ... 4 



Styles united half way up . . . Spartina. 



Styles distinct .... 5 



Glumes nearly equal .... Oynodon. 



Glumes very unequal .... Digitaria. 

 Spikelets imbedded in the rachis . . Rottbolia- 



Spikelets not imbedded ... 7 



Spikelets two or more from same point . .11 



Spikelets solitary .... 8 



Spikelets one-flowered . . . Knappia. 



Spikelets more than two-flowered . . 9 



Glume solitary, inclosing the spikelet between it and rachis Lolium. 

 Glumes two, their edges towards the rachis . .10 



Florets equal . . . Brachypodium. 



Florets smaller upwards . . . Tritioum. 



Spikelets one-flowered .... Hor&eum. 

 Spikelets two or more flowered . . . Elymus. 



Calyx one-flowered .... 13 



Calyx two or more flowered . . .23 



Glumes -with feathery awns . . . Lagurus. 



Glumes awnless, or awns not feathery . . 14 



Panicle dense, (subspiked,) florets mostly imbricated 15 



Panicle loose, florets not imbricated . . .20 



Corolla with tuft of hair at base . . Amophilla. 



Corolla without hairs at base . . .16 



Corolla with one or two valves of imperfect florets at base PMlaris. 

 Corolla without valves of imperfect florets at base . 17 



Corolla awnless .... Phleum. 



Corolla awned . . . . .18 



Corolla of one valve, the awn basal . . Ahpecurus. 



Corolla of two valves, the awn terminal or dorsal . 19 



Glumes awned, awn of corolla terminal . . Polypogon. 



Glumes awnless, awn of corolla dorsal . Gastriiium. 



Fruit inverted with the hardened corolla; corolla awnless 21 

 Fruit not inverted with the corolla; corolla often awned 22 



Corolla with a small valve at the base 

 Corolla without a valve at the base . 

 Corolla with long hairs at base . 

 Corolla without hairs at base 

 Florets with a pinnated bractea 



Phalaris. 



. Milium. 



Calamagrostis. 



. Agrostis. 



Cynosurus. 



