HOW TO KNOW THE GRASSES 



12a. Spikelets with only one perfect floret, sometimes with unlike stami- 

 nate, empty, or rudimentary ones above or below it 13 



12b. Spikelets with several perfect or pistillate florets 27 



13a. Entire spikelets breaking from the plant 

 when ripe. Fig. 27 14 



Figure 27 



13b. Spikelets when ripe breaking off above the 



glumes, leaving them on the plant. Fig. 28 



23 



Figvire 28 



14a. Both glumes absent or reduced to minute ridges be- 

 low the lemma and palea; spikelets strongly later- 

 ally flattened, with strongly keeled lemma and 

 palea. Fig. 29.... TRIBE IX, ORYZEAE, page 146 



Figure 29 



14b. At least one glume well developed; spikelets flat or roimd in 

 cross section *^ 



18 



