GROWTH 



121 



embryonic parts within the bud begin to enlarge and this 

 helps to force the bud-scales apart. The young stem-in- 

 ternodes rapidly elongate, the petioles of the leaves in- 

 crease in length, and gradually the leaf-blades expand 



Fig. 8o. — Sapling of horse-chestnut {Msculus Hippocastanum), with young 

 leaves not yet wholly expanded. (Cf. Fig. 79.) (Photo by the author.) 



as their cells become more and more turgid (Figs. 79 

 and 80). 



123. Permanent and Temporary Growth. — The size 

 finally attained by stems, roots, leaves, and other parts 

 is usually permanent; but some growth is temporary, 

 and certain tissues may manifest various alterations in 



