ROOTS 



295 



together. On this account, the leaves, which on the 

 grown stem are far apart, overlap one another in the bud, 

 and form a compact bundle. This pro- 

 tects the tip of the branch until it is 

 ready to grow. The most common buds 

 are dry and shiny on the outside, and 

 are planned to keep out moisture. In 

 winter buds the inside of the leafy covers 

 is often wooly, in order to protect the 

 young leaves and stem from sudden 

 changes of weather (cf. 75). 



Ovules 



Stem 



Ovary 



FIG. 243. Cross Section 

 of a Rose Bud. 



The " growing tip" of each stem and branch has a terminal, or 

 "end," bud. Buds that arise in the axils of leaves (cf. 312) are called 

 axillary buds. Buds that occur in unusual places, that is, not at the 

 tips of branches or in the axils of leaves, are called "unusual," or 

 adventitious, buds. The young shoots that are sent up by the stump 

 or the root of a tree are from adventitious buds. 



316. Roots. The work of the leaves and the stem is 

 carried out in the air and the light; hence these parts 

 develop upward when the seed ger- 

 minates. But the duty of the root is to 

 hold the plant in a fixed place, and to se- 

 cure water and food for it from the soil. 

 The roots of common plants avoid 

 the light just as strongly as leaves and 

 stems seek it. Some roots, however, 

 such as those of water plants, carry on 

 FIG. 24i. Kinds of Roots, their functions outside of the soil. 



The root that comes from the hypocotyl, and all that develops from 

 this root, is called the primary root. Sometimes the primary root goes 

 down in one main portion, called a tap root (Fig. 241). The dandelion 



