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. 80. Sapling of horse-chestnut (AL$culus Hippocastanum), 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 
