THE STEM , 197 
The cambium ring adds more xylem elements called secondary 
xylem on its inner face and more phloem elements called secondary 
hyma of Cortes 
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Fic. 127.—A diagram to show the character of the tissues and their disposition 
in a young stem of the typical dicotyledon type. (From Stevens.) 
_ phloem on its outer face. As it cuts off sieve tubes and companion 
cells outwardly and tracheze and wood fibers inwardly all along 
the line it also cuts off here and there a medullary ray cell on 
