EXPLANATION OF PLATE VTTT. 



POLYPOGON. — (1) Spike-like contracted panicle of P. Monspeliensis ; 

 '2) an enlarged detached spikelet, showing the long aAvns to the empty 

 glumes; (3) the same open in flower; and (4) a separate flower without 

 the empty glumes. 



CINNA. — (1) A magnified spikelet of C. arnndinacea; and (2) the same 

 open, displaying the flowering glume and palet, the single stamen, and 

 the pistil. 



MUHLENBERGIA. — (1) A magnified closed spikelet of M. sylvatica ; 

 (2) the same with the open flower raised out of the empty glumes. — (3) A 

 magnified spikelet of M. diffusa ; (4) its minute and unequal empty glumes 

 more magnified; and (5) an open spikelet of the same. 



BRACHYELYTKUM.— (1) A spikelet of B. aristatum enlarged; (2) the 

 same displayed. 



CALAMAGROSTIS. — (1) An open spikelet of C. Canadensis, enlarged, 

 displaying all the parts; (2) the same with the flower raised out of the 

 empty glumes, showing the hairy rudiment behind the palet. 



ORYZUPSIS. — (1 ) An open magnified spikelet of (). asperifolia; and (2) the 

 flower of the same removed from the empty glumes. Notice the remark- 

 ably long squamulai or liypogynous scales, which here nearly equal the 

 glume in length. 



STIPA. — Empty glumes and flower (a little separated) of S. avenacea, 

 enlarged. 



ARISTIDA. — A spikelet of A. purpurasceus, enlarged. 



