14 LSSSONS WITS PLANTS 



15. The pupil should now examine the grape- 

 vine, and thoroughly master its method of branen- 

 ing. He will find that the trunk is not formed 

 by continuous growth from a terminal bud, but 

 from lateral buds. That is, the continued progress 

 in stature is made by successive lateral branches 

 or secondary leaders, each of which has been a 

 leader in its turn. This is a type of diffuse 

 branching, in distinction to that of those plants 

 which grow constantly onward from the terminal 

 bud, in a strict or straight fashion, of which the 

 firs are typical examples. The pupil will now 

 observe the method of branching of the various 

 trees and shrubs which he meets, and determine 

 which ones retain the leader throughout life. 

 He will also be interested in the dry stalks of 

 herbs, as mulleins and thistles, which stand in 

 the waste places all winter. He will find that 

 most trees are at first strict and afterward diffuse. 

 Continued growth of the leader results in inde- 

 terminate or excurrent forms of trees, while the 

 diffuse method results in determinate or deliques- 

 cent tree tops, like those of the elms and apple 

 trees. 



Suggestions, — The pupil phould now explain why and when 

 the common trees change from the strict to the difEuse 

 style of branching ; and lie should endeavor to figure out the 

 exact year in which the terminal bud was lost in certain small 



