104 



PLANT LIFE. 



in pairs, a phloem (bast) bundle and a xylem (wood) bundle 

 being placed side by side, the xylem occupying the side next 



Fig. 119. — Portion of a transverse section of the stem of flax, m, pith; h, secondary 

 xyiem forming a woody cylinder ; pk , phloem ; 6, bundles of mechanical tissue (fibers) 

 among the thin-walled cells, the two sorts making up the cortex; e/l, the epidermis. 

 Magnified about 25 diam. — After Prank. 



P 



Fig. 120. — Transverse section of a bundle pair from the stem of a begonia. The shaded 

 part is the xylem bundle; the small irregular cells above are the phloem bundle; 

 between them is a zone of generating tissue (secondary meristem), the stelar cambium, 

 which extends also right and left of the bundle pair. The radius of the section passes 

 through CP; C, next the center. Magnified 150 diam. — After Haberlandt. 



the center of the stem, and the phloem the side next the 

 surface (figs, in, 120). The number and position of these 



