96 



PRACTICAL BOTANY 



Evidently when the spur produces a terminal bud contain- 

 ing flowers it cannot grow straight ahead but must turn aside 



sc- 



FIG. 79. Cross section of a poplar bud 



sc, bud scales ; I, leaves ; st, stipules. Magnified 

 15 diameters. After Strasburger 



FIG. 78. A lengthwise 



section of bud of thorn 



tree (Cratcegus) 



br, brown outer bud 

 scales ; o, pale bud scale ; 

 i, innermost rudimentary 

 leaves ; g, growing point 

 at apex of twig, consisting 

 of cells in a condition to 

 sub-divide and multiply 

 rapidly at the beginning 

 of the growing season. 

 Somewhat magnified 



slightly. Since a large part 

 of the plant food carried into 

 the spur is used in produc- 

 ing the flowers and fruit, it 

 is clear that a fruit spur 

 cannot grow as rapidly as 

 an ordinary twig. A little 

 study of an old fruit spur 

 will show that of the scars 

 left by the flower buds 



FIG. 80. American elm, March 11 



The large buds are flower buds, the smaller, 

 more numerous ones, leaf buds. Reduced 



