GENERAL SURVEY 



25 



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' \ /N -/ ' '■'■■' '"Cainblum' 

 V Ajrlem from the procambium 

 Xylem from the cambium 

 Phloem, from the procambium and camlilum 



Xylem from the procambium 

 Xylem from the cambium 

 Phloem from the procambium and cambium 



Fig. II. — Diagram showing the evolution of tissues from the primordial meristem 

 down to the beginning of cambial activity. In the longitudinal diagram, at the bottom 

 the intial C of the word cambium stands directly beneath this tissue which is radially but 

 one cell in thickness. 



lary rays lie between the bundles, and are limited externally by 

 the plane touching the outer borders of the phloem strands, 

 and internally by the plane bounding the inner borders of the 

 xylem strands; while the medulla or pith is all of the tissue 

 surrounded by the bundles. Everything within the starch 

 sheath is called the stele. 



