EXPLANATION OF PLATE XL 



UNIOLA. (1) A spikelet of U. latifolia, of about the natural size; (2) a 

 flower, enlarged ; (3) empty flowering glume of the lowest (sterile) flower. 



PHRAGMITES. ( 1 ) A spikelet of P. communis, enlarged ; (2) one of the 

 perfect flowers, enlarged ; and (3) the lowest flower, which has stamens 

 only. 



ARUNDINARIA. (1) A spikelet of A. macrosperma ; and (2) a separate 

 flower, magnified. 



SCHEDONNARDUS. (1) Portion of the spike of S. Texanus, enlarged; 

 and (2) a flower, magnified. 



LOLIUM. (1) Portion of the spike of L. temulentum; and (2) a separate 

 flower, magnified. 



AGROPYRUM. ( 1 ) Portion of the spike of A. repens, or Couch-Grass, of 

 about the natural size ; (2) a flower, magnified. 



HORDEUM. (1) The three one-flowered spikelets from one joint of the 

 spike of H. jubatum, with their awn-like empty glumes, the lateral flowers 

 abortive and neutral, the middle one alone perfect; (2) this perfect flower 

 (with an awn-like rudiment) open and enlarged. 



EL YMUS. (1 ) The two spikelets of one joint of the spike of E. Virginicus, 

 about the natural size ; (2) the empty glumes and the flowers of one spike- 

 let, enlarged and displayed ; and (3) an open flower, more magnified. 



ASPRELLA. (1) A spikelet of A. Hystrix; and (2) an expanded flower, 

 magnified. 



