228 



COMPARATIVE ANALYSIS. 



3. Calyx many-flowered ..... Triticum. 

 Calyx one or two-flowered . .4 



4. Styles united half way up . . . Spartina. 

 Styles distinct . . . . . .5 



5. Glumes nearly equal ..... Cynodon. 

 Glumes very unequal .... Digitaria. 



6. Spikelets imbedded in the rachis . . . Rottlolia. 

 Spikelets not imbedded . . . . .7 



7. Spikelets two or more from same point . . .11 

 Spikelets solitary . . . . . .8 



8. Spikelets one-flowered . . . . Knappia. 

 Spikelets more than two-flowered . . . .9 



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

 Glumes two, their edges towards the rachis . . 10 



10. Florets equal .... Brachy podium. 

 Florets smaller upwards .... Triticum. 



11. Spikelets one-flowered .... Hordeum. 

 Spikelets two or more flowered . . . Elymm. 



12. Calyx one-flowered . . . . .13 

 Calyx two or more flowered ... 23 



13. Glumes with feathery awns .... Lagurus. 

 Glumes awnless, or awns not feathery . . 14 



14. Panicle dense, (subspiked,) florets mostly imbricated . 15 

 Panicle loose, florets not imbricated ... 20 



15. Corolla with tuft of hair at base . . . Amophilla. 

 Corolla without hairs at base . . . 16 



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

 Corolla without valves of imperfect florets at base . 17 



17. Corolla awnless ..... Phleum. 

 Corolla awned . . . . . 18 



18. Corolla of one valve, the awn basal . . . Alopecurus. 

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



19. Glumes awned, awn of corolla terminal . . . Polypogon. 

 Glumes awnless, awns of corolla dorsal . . Gastridium. 



20. Fruit inverted with the hardened corolla; corolla awnless . 21 

 Fruit not inverted with the corolla; corolla often awned 22 



21. Corolla with a small valve at the base . . . Phalaris. 

 Corolla without a valve at the base . . . Mitium. 



22. Corolla with long hairs at base . -. Calamagrostis. 

 Corolla without hairs at base . . . Agrostis. 



23. Florets with a pinnated bractea . . Cynosurus 

 Florets without a, pinnated bractea . . . . 24 



24. Calyx with not more than two perfect florets . . 25 

 Calyx with more than two perfect florets . . 35 



25. Panicle dense, in a simple or compound spike . . 26 



