232 HANDBOOK OF NATURE STUDY 



shape ; have only a short stalk ; their margins are serrate, 

 or toothed, but show no large lobes. Which of these are 

 smooth, and which are rough or hairy ? 



2. The leaves of most of our common oaks are deeply 

 lobed, and have only a short stalk, or petiole. The leaves 

 of most of the black oaks terminate their lobes in a fine, 

 needle-shaped point, while the white oaks show rounded 

 lobes. Are oak leaves smooth, glossy, or downy ? Do they 

 look alike on both sides ? Do elms or oaks present the 

 more densely massed foliage ? 



3. Here we have leaves that grew on the sugar maple, 

 the silver maple, and the wild grape vine, respectively. 

 How does the length of the leaves compare with the length 

 of the petiole ? How can you distinguish the three kinds 

 from one another ? How do these leaves differ from oak 

 leaves, and from the leaves we placed in the first group ? 



4. The leaves of the quaking asp, the cottonwood, and 

 the birches have a long, slender petiole, and are moved by 

 the slightest breeze. Have you ever heard the lisping, 

 whispering sounds of poplar groves on a summer day? 

 What effect has a strong wind upon poplar leaves ? Why 

 should one of the poplars be called the quaking asp ? 

 Break some poplar petioles by pulling. Why is it neces- 

 sary that the petioles should be strong ? How does the 

 width of these leaves compare with their length ? Are 

 the veins more prominent than in maples and oaks ? 



5. Willow leaves are much longer than wide. Describe 

 their margins. The leaves of the linden are quite broad, 

 and distinctly heart-shaped. How does their venation com- 

 pare with that in poplar leaves ? 



All the leaves we have examined thus far had each a 

 separate petiole, which issued directly from the woody twig; 



Observations. Where is the most beautiful autumn grove you know of ? 



