307 



GRAMINEAE. 



Key to genera. 



(In this and subsequent keys glume r is the outer one, glume ii the 



next and so on.) 



1. Spikelet with 1 fertile flower with or 



without a second male one below it 

 Spikelet with 2 or more heramphrodite 

 flowers or the upper unisexual 



2. Spikelets or spikes more or less pedi- 



cellate in an irregular spreading or 

 spike-like panicle ... 

 Spikelets sessile or in pairs, one sessile 

 one pedicellate, or subsessile, in a 

 spike or on the spike-like branches 

 of inflorescence 



3. Spikelets not in distinct rows, but 



sessile or shortly pedicellate, form- 

 ing a dense cylindrical spike or 

 spike-like panicle .... 

 Spikelets singly sessUe or in pairs, in 

 2 or 4 rows, in a simple usually 

 1-sided spike or on the sessile spike- 

 like branches of a simple panicle... 



4. Spikelets awned 

 Spikelets awnless 



5. Only flowering glumes awned... 

 Outer glumes awned ... 



6. Spikelets flat, awn on back of glume... 



Spikelets not flat, awn terminal 



7. Awns of spikelet 2-3 



Awns of spikelet 1 



8. Axis of spikelet produced and peni- 



cillate with long silky hairs 

 Axis not produced 



9. Racemes simple ; awns much longer 



than glumes 

 Panicle branched but dense spike-like ; 

 awns very short 



10. Spikelets surrounded by bristles or hairs 

 Spikelets naked 



11. Spikelets surrounded by bristles 

 Spikelets surrounded by silky hairs ... 



12. Spikelets in spike-like panicle 

 Spikelets in epikes or racemes 



47. 



29. 



2. 



69. 



45.. 



14. 



5. 



10. 



6. 



9. 



Alopecurus 



325). 



7. 



Pogonatherum (p. 



320). 



(p. 



52. Dei/euxia(Tp.326). 

 51. Galamagrostis (p. 

 326). 



22. Perotis (p. 318). 



50. Polypogon (p. 

 326). 

 11. 

 13. 

 12. 

 24. iw!/ieraia(p.318). 

 9. Setaria (p. 316.). 

 10. Pennisetum (p. 

 316.) 



TJ 2 



