468 GRAMINEjE. 



Tribe V. AVENE'ffi. Spikelets panicled, terete or laterally compressed, 

 2- rarely 3-4-fld. ; rachilla produced beyond the fl. glume (except in 

 some Airce). Glumes 4 or more, 2 lowest empty usually larger than 

 the others, 2 or more upper flowering with a dorsal bent and twisted 

 (except some Airce and Deschampsice) awn. 



* Rachilla not produced beyond the uppermost jl. glume 20. Aira. 



** Rachilla produced beyond the uppermost jl. glume ; Jlowers all perfect or the 

 upper imperfect. 



Flowers 2 ; awn bent in the middle, tip clubbed 21. Corynephora. 



Flowers 2; awn straight 22. Deschampsia 



Flowers 2 ; lower not awned, upper imperfect awned 23. Holcus. 



Flowers 2-6; fl. glume deeply 2-fid and awned 24. Trisetum. 



Flowers 2-6; fl. glume entire or 2-toothed, long-awned 25. Avena. 



*** Rachilla produced beyond the fi. glumes. Flowers 2, upper 2-sexual, lower 

 male 26. Arrhenatherum. 



Tribe VI. CHLORIDES. Spikelets 1-2-seriate on a flattened rachis, 

 laterally compressed, 1- or more-fid 27. Cynodon. 



Tribe VII. FESTUCE'iE. Spikelets panicled or subspicate, terete or 

 laterally compressed ; rachilla usually produced beyond the fl. glume, 

 often bearing a rudimentary glume. Glumes 6 or more, 2 lowest empty, 

 the others flowering ; awn terminal or 0. 



Sub-tribe 1. Triodiese. Spikelets % or more-fid.; rachilla not bearded. 

 Fl. glumes 1-3-nerved, broadly 3-toothed 28. Triodia. 



Sub-tribe 2. Arundineae. Spikelets 2- or more-fid. ; rachilla bearded 

 with long silky hairs 29. Phragmitis. 



Sub-tribe 3. Sesleriese. Spikelets subspicate or capitate, with empty 

 glumes (imperfect spikelets) on the pedicels below them. 



Pedicels with soft glumes below the spikelets 30. Sesleria. 



Pedicels with bristle-like glumes below the spikelets 31. Cynosurus. 



Sub-tribe 4. Eragrostese. Spikelets 2- or more-fid. Fl. glumes 1- or 

 S-nerved. 



Spikelets in a subcylindric spike. Fl. glumes scarious 32. Koeleria. 



Spikelets in a contracted panicle, conical, terete 33. Molinia. 



Spikelets in an effuse panicle with whorled branches 34. Catabrosa. 



Sob-tribe 5. Melicese. Spikelets 2- or more-fid. Fl. glumes 3-5-nerved, 

 upper empty, convolute and forming a club 35. Melica. 



Sob-tribe 6. Eufestucese. Spikelets S-many-fid. Fl. glumes 5- or more- 

 nerved. 



Spikelets few-fld., clustered in a secund panicle 36. Dactylis. 



Spikelets panicled, pendulous. Glumes broad, scarious, obtuse. 



37. Briza 

 Spikelets panicled. Fl. glumes compressed, keeled, tips nerved 



awnless. 38. Poa. 



