122 



STEMS 



The Bark. Describe the bark, noting color, smoothness 

 or roughness, etc. Look for the lenticels (breathing pores). 

 Can you discover any system in their arrangement ? Is the 

 bark of the same hue on both sides ? If darker on one side 

 than on the other, how can you account for it ? Is there any 



way of telling whether 

 the twig grew in a vertical 

 or a horizontal position 

 on the tree? Reasons 

 for your judgment. 



Remove the outer layer 

 of bark and describe 

 what lies below it. How 

 many distinct layers can 

 be removed? 



Scars. How many 

 kinds of scars can you 

 find on your specimen? 

 What is the shape of 

 the leaf scars (traces) on 

 this twig? Draw a leaf 

 scar enlarged. What 

 scars are found in angles 

 between two forking 

 twigs ? Their cause ? 

 Do these scars show any dots like those seen in a leaf scar ? 

 Why not? Look for node lines (ridges joining opposite leaf 

 scars). Split a twig open through the center and observe the 

 structure at the region of a node. 



Count the dots on several leaf scars and determine 

 whether the number is uniform or not. Account for these 

 dots. 



FIG. 47. Hickory bud, dissected, showing 

 modifications of bud scale. 



