88 MEDULLARY RAYS 



angles to the rays, called a tangential section, we see that the cells 

 of the rays are arranged in a lens-shaped group (Figs. 58, mt; 

 59, B). The medullary rays are of great importance in the dis- 



FlG. 58. Diagram of a three-year-old stem of basswood cut so as to show 

 the structure in cross-section, C, in radial section, R, and in tangential section, 

 T; c, cortex; ck, cork; ph phloem with darker bands of stereome; mc, medullary 

 ray in cross-section; mr, ray in radial section; mt, ray in tangential section; 

 /, lenticels; cam, cambium cylinder; p, pith. — H. O. Hanson. 



tribution and often also in the storage of foods. Their structure 

 and arrangement in the stem are admirably adapted for this work. 



