APEX OF ROOT 



Apex of the Root. 



Type l.Using the fruit of the Sunflower in the dry state, as 

 it may be bought in seedsmen's shops, cut thin median longi- 

 tudinal sections of the apex of the radicle of the straight 



pr.xy 



fctt^ 



FIG. 8. A. Diagram illustrating the disposition of tissues in the young root of a 



Dicotyledon, before the camoial divisions begin. 



The same at a later stage, when the cambium may be clearly recognized. 

 C. Diagram of arrangement of tissues in the root, after secondary thickening has 

 been in progress for a considerable time : in such a root the cortex, which is seen 

 as a broad band (c) in Figs. A, B, has been completely thrown off, and the section 

 is now limited by tissue (J>) derived from the deeper-lying pericycle. 

 c = cortex ; p = pericycle ; pr.xy = protoxylem ; pr.phl = protophloem ; m = 

 pith ; cb = cambium ; xy 1 ' = secondary xylem ; ////" = secondary phloem ; 

 p.mr-=. primary medullary rays ; nn" = secondary medullary rays. 



embryo. The arrangement of the meristem at the apex of 

 the radicle of the embryo is similar to that of the apex of the 

 growing root, and the former is chosen in this case as it is much 

 easier to make preparations from it than from the growing 



