GRASSES OF IOWA. 



47 



has no blade, and the palea resembles it in being almost always 

 (excepting Amphipogon) awnless; and as the former is some- 

 times split in two parts (Cynodon), so the palea is often split 

 at the time the fruit is mature (many Sporoboli and Triticum 

 monococcum L.). This state has been understood by some 

 authors as originally bifoliate, and false genera have been 

 established upon it by some (Diachyrium Griseb, etc.). The 

 palea is completely aborted in many And ropogoneae and species 

 of Agrostis. " 



The axis to which these 

 glumes are attached is 

 termed the rachilla, and 

 between each flower and 

 this rachilla there is usual- 

 ly a two-nerved bract, the 

 palea, theprophyllumtothe 

 floral branch. In one- flow- 

 ered spikelets where there 

 is no extension or prolonga- 

 tion of the rachilla, this 

 palea is apparently oppo- 

 site the flowering glume. 

 The lower pair of glumes — 

 the empty ones — often differ 

 from each other in size or 

 length, and sometimes, 

 though rarely, one or both 

 are absent. In others they 

 occur as rudiments, as in 



Leersia. In a few cases it ^ Fig 38 EragrostUtriclwdes. Loose pa.aicnla.te 



consists of but a few scales, 



Inflorescence. 





Fig. 39. Showing lodicules below stamens 

 3, Melica nutans. (After Nees, Hackel ) 



1. Paniciim miliaceum; 2, Avena sativa; 



