196 



Mineral Nutrition of Plants 



Figure 3. Longitudinal sections of the apex of a root of curley-top to- 

 bacco. Details: c, regions of cortical initials; e, endodermis; p, pericycle; 

 s, region of stele initials. A, above, shows spatial order of differentiation 

 of endodermis and phloem relative to the meristem. B, below, shows early 

 differentiation of cortex and stele from meristem initials. — Esau (23) 



