THE WALLFLOWER 



51 



Many of these cells are quite empty that is to say, 

 they have no living contents, and only contain air or 

 water. This inner half of the bundle is the wood or 

 xylem (x in Figs. 20 and 21). 



-px. 



FIG. 21, Transverse section through a vascular bundle of a 

 young stem of Wallflower, en, endodermis, containing 

 starch granules ; pc, pericycle ; ph, phloem ; c, cambium ; 

 x, xylcm or wood ; px, protoxylem, or first-formed wood. 

 Portions of pith, mterfascicular tissue, and cortex aro 

 also shown. Magnified about 210. (R. S.) 



The outer part of the bundle, lying towards the 

 cortex, consists of much smaller cells, with thin walls 

 of pure cellulose, and with abundant protoplasmic 



