The Intake of Carbon 201 



all exposed vegetative organs, but the leaves are primarily 

 the seats of their occurrence. The palisade and general 

 parenchyma cells of the leaf ordinarily contain many 



i . . 



FIG. 55. Abutilon ; looking down upon the plant shown in Fig. 54. 



chloroplasts (Fig. 25). Such tissue is designated chlor- 

 enchyma. In stems or other thick organs the chloren- 

 chyma is comparatively near the surface ; for, as a rule, the 

 formation of chlorophyll is directly or indirectly dependent 



