GENERA OF GRASSES OF THE UNITED STATES. 



57 



3-nerved, the lateral nerves sometimes faint or obscured by stria- 

 tions and intermediate nerves; lemmas closely imbricate, firm, the 

 pistillate coriaceous, the margins bowed out near the base, acute or 



acutish, 3-nerved, with several intermediate nerves or striations; 

 palea as long as the lemma or shorter, the pistillate coriaceous, in- 

 closing the grain. 



