102 



BOTANY 



coldest months of the year. The factors which influence the ger- 

 mination of seeds also act on the bud. 



Position of the Bud on the Stem. — The growth of the stem 

 from the bud can best be observed in a very young seedling. If, 

 for example, we examine a pea seedling, it will be seen that the 

 epicotyl is, in truth, the first bud of the plant. It produces the 

 first stem and leaves. The position of the most active buds deter- 

 mines the form of the future tree. Buds come out at the ends of 

 branches {terminal) and at the sides {lateral). 



Deliquescent Tree. — If you examine a winter branch of the 

 apple, elm, or oak tree, you will find that the lateral buds have 



Excurrent trees (at right) and deliquescent tree (at left). In background a row of cedars 

 which were planted by birds roosting on a fence along a roadside. 



developed more strongly and more rapidly than the terminal bud. 

 Thus the tree has come to assume during its growth a rounded 

 shape. Such a tree, having a rather stout, short trunk, with 

 many low, spreading, lateral branches, is said to be deliquescent. 



Excurrent Tree. — If, on the other hand, the terminal buds of 

 the tree get a better supply of light, food, or if other factors aid its 

 growth, the tree will be tall and have but one main trunk, such 

 as the Lombardy poplar, and pines and cedars. Such a tree is 

 named excurrent. The picture shows trees of these two shapes. 



Structure and Functions of the Parts of a Winter Twig. — The 

 best way for us to understand the growth of a bud into a branch 



