36 



Fig. 10. 



MONOCOTYLEDONEJE. 



Fig. 11. Fig. 12. 



Germination of 

 Barley. 



Germination of 

 Wheat. 



Development of 

 perennial Gramineae. 



The culms are incipiently depressed cones ; in 

 this state they exist, no doubt, even in the seed. 

 Those of wheat generally consist of eight joints ; 

 the first and second at the bottom, if the grain has 

 been deposited at the proper depth, are short, every 

 higher one increasing in length the last bearing the 

 ear being the longest. The culms progress in height 

 by the inflation and perpendicular extension of the 

 large cells occupying the centre between the joints, 

 and of the denser cellular tissue composing the ex- 

 terior cylinder. The latter is also inflated horizon- 

 tally ; its inner side becoming vascular, and forming 

 the principal channel for the ascent of the sap. The 

 exterior surface of the stem is somewhat fluted, dense, 



