THE SKELETON OF THE PLANT 43 
complexity as its life continues. In every plant growth 
proceeds continuously or intermittently so long as life lasts. 
<e\e 
Mone 7 
Dereon 
WL tate 
Fira. 40.—Diacram or Stem or Dicorynmpon ar Turme AGEs. 
a, Young condition showing the first formed vascular bundles a. B, A little older 
stage, showing preparation for formation of new conducting tissue. oc, Older 
stage. The bundles have become larger and new ones (a) have been intercalated 
between them. 
Every year new branches or twigs with their associated leaves 
are constantly produced. With such continuous increase 
of size, new conducting tissue must be formed. The skeleton 
