F. C. Miles 211 



light passes through the several layers which are void of plastids. 

 It was noted that the stripe which appeared a pale green on the 

 upper surface of the leaf was of a more intense green colour on the 



Fig. 7. Cross section through a greeu portion of a leaf 

 of the striped race Zea japonica. Plastids are dis- 

 tributed through the different cell layers. x 3.50. 



Fig. 8. Cross section through a pale green stripe of a 

 leaf of the striped race Zea japonica. Apparently 

 normal plastids are found in the cells near the 

 lower epidermis, and light passing through the 

 colourless layers above causes a reduction of 

 the intensity of the green colour, x 300. 



lower surface. This would be expected because if the leaf be viewed 

 from the lower surface the cells containing chloroplasts would be 

 immediately underneath the epidermis, and consequently the green 

 would show more vividly than if the light had ti) pass through several 

 layers of cells. 



