104 



LEAVES AND FOLIAGE 



of leaves? How is the form of leaves associated with their function? 

 What are simple leaves? Compound? What is venation? What are 

 the types or kinds of venation? What are the two types of compound 

 leaves? What is a leaflet? Define bi-compound; decompound. 

 What are lobed, cleft, parted, and divided leaves? Pinnatifid 

 leaf? Complete leaf? Complete leaflet? What is a sessile leaf? 

 How may the petiole join the blade? How are the shapes of leaves 

 named or classified? Define the shapes described in 210. Describe 

 common shapes of the base of the leaf. Of the apex. Of the margin. 

 How are the forms and sizes of leaves ever related to the place in which 

 they grow? Why do leaves fall? Define deciduous. Persistent. Ever- 

 green. When do pine leaves fall? How can you distinguish leaves? 



158. Shoot of the common white pine, one-third natural size. 

 The picture shows the falling of the leaves from the different years' growth. The 

 part of the branch between the tip and A is the last season's growth; between A and 

 B it is two years old; the part between B and C is three years old; it has few leaves. 

 The part that grew four seasons ago — beyond C — has no leaves. 



