PE DICE LED SPI RELETS WITH LARGE GLUMES 45 



florets removed from the glumes. Note the curved 

 and exceptionally long lowermost rachilla joint.) 



In Sphenopholis, closely related to Trisetum 

 (Fig. 32), the spikelets fall entire, as in velvet-grass. 

 In tall oat-grass (Arrhenatherum elatius) the spikelets 

 bear one perfect awnless floret and one staminate 

 awned floret, as in velvet-grass, but their position is 

 reversed, the staminate being below and the perfect 

 above. 



SUMMARY 



In the oat and its relatives the large glumes and 

 the awn of the lemmas are the most prominent 

 characters, although in species of some genera the 

 awn is wanting. Pubescence is commonly con- 

 spicuous. The inflorescence is an open or contracted 

 panicle. 



REVIEW 



Collect panicles of wild oats or awned specimens of cultivated 

 oats (cultivated oats growing wild commonly bear awns), of 

 Danthonia, one or more species of which are to be found through- 

 out most of the United States, and any of the related grasses 

 available, and examine the spikelets. Place a floret with a 

 twisted awn in a drop of water and observe the result. In awn- 

 less florets of cultivated oats note that the midnerve of the lemma, 

 if it is not at all produced into an awn, stops abruptly at the 

 point where the awn would arise normally and that the lemma is 

 nerveless above this point, just as if it were awned. 



