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 Hippocastanwn), with young 

 leaves not yet wholly expanded. (Cf. Fig. 79.) 



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 



