MERISTEM. 



51 



(li.) An outer part made np of thin-walled elements, the rudimentary 

 phloem, or pFOtOphloem. 



(m.) An intermediate part composed of thin-walled meristematic cells, 

 the rudimentary cambium of the primary vascular bundles (fascicular 

 cambium). 



Further down the stem the primary bundles are differentiated 

 into typical xylem, cambium, and phloem, and between the 

 primary bundles it is found that certain cells of the ground-tissue 

 have remained or have subsequently become meristematic ; these 



Fig. 34. — A Longitudinal Section through the Apex of a Young 

 Shoot (Dicotyledon or Pinus). — d, Dermatogen ; p, periblem ; pc, 

 procambial strands ; m, medulla ; b, bracts ; k, leaf-buds ; I, lateral 

 offshoots from procambial strands. The portion included between the 

 procambial strands {pc) is the " central cylinder." 



cells, in fact, will give rise to intermediate patches of cambium, 

 the so-called interfascicular cambium. The interfascicular cam- 

 bium produces, in like manner to the cambium of the primary 



