THE NUTRITIVE ORGANS OF PLANTS 



53 



A. Leaf scars. (The horseshoe-shaped scars with the raised dots 



like horseshoe nails indicate the places where the stalks 

 of the leaves were attached.) 



1. Do the leaf scars occur in pairs, or is there only one scar 



at a given level? How, therefore, were the leaves ar- 

 ranged on the 

 stem? 



2. Count the num- 



ber of dots on 

 several differ- 

 ent leaf scars ; 

 these dots are 

 the ends of 

 the wood 

 bundles that 

 carried sap to 

 the various 

 leaflets. Look 

 at the picture 

 ofhorse-chest- 

 nut leaves. 

 (See Fig. 20, 

 K.) How 

 many main 

 veins do you 

 find in one 

 compound 

 leaf? Com- 

 pare this 



number with the number of dots on the leaf scars ; what 

 do you conclude ? 



B. Buds. (At the end of most twigs is a single terminal bud; 



the buds along the side of the twig are lateral buds. 

 Each bud is covered with bud-scales.) 



1. State the position of each kind of bud on the twig. Where 

 are the lateral buds found with reference to the leaf scars ? 



FIG. 19. Spray of young apple tree, showing 

 alternate arrangement. At the base of each 

 leaf stalk is a pair of small stipules. (Bailey.) 



