CHAPTER III. 



STEM- AND TOP-GROWTH, APPENDAGES, AND 

 CIRCULATION. 



22. Stem-growth. After the seed is established by 

 starting rootlets the upward-growing shoot, or plumule, 

 starts growth and soon forms perfect leaves. The root- 

 growth, after the first extension of the 

 hypocotyl, is by cell-growth at the tips 

 something like the extension of an icicle 

 except that the ice lengthens by addition 

 from the outside and the root by the cell- 

 growth within. The stem makes each year's 

 growth by elongation usually at one time 

 in the spring, something like the stories of a 

 building. Each story of growth when young 

 is shown by a slight enlargement, or by the 

 leaf -scars as shown in Fig. 4. At the point 

 between the one- and two-year old wood, 

 called the node, most starch is stored at the 

 base of the buds. Hence in making cuttings 



of the new wood of tne g^P 6 and man y 

 trees and shrubs the node is included, as 

 roots more readily start from this point. 

 The part between the buds, known as the 

 internode, after completion of its elongation, remains 

 stationary. It increases in diameter, but never in length. 



20 



FIG. 4. 

 Union of new 



and older 



wood. 

 (After Goff.) 



