CHAPTER IX. 



THE SHOOT. 



87. Primary shoot. — The first shoot which develops is 

 called the primary shoot. Rarely no primary shoot develops. 

 Sometimes the primary shoot early ceases to grow, and its 

 place is taken by secondary shoots arising from the root. 



The tip of the shoot is the region in which the formation 

 of new cells is taking place. This region of young cells has 

 no definite limit below, but passes insensibly into the older, 

 which it produces. The tip of the shoot may be either a 

 sharp cone or a low dome. Between these forms a complete 

 series of gradations exists. Close below the apex the shoot 

 begins to show a differentiation into a central axis and lateral 

 outgrowths. The first of these to appear are swellings which 

 form the leaves. Later, above the leaf rudiments, the rudi- 

 ments of the lateral shoots may appear. The older leaves upon 

 the sides of the axis outgrow the younger ones and the de- 

 veloping axis, and arch over them in such a way as to form 

 a more or less compact structure, which is a terminal hud. A 

 bud is, then, an undeveloped shoot, whose older leaves pro- 

 tect the younger, and particularly the youngest region, the 

 apex (fig. 58). From the terminal bud arise all the mem- 

 bers of the primary shoot. 



88. Differences from root. — From what has been said of the origin of 

 the shoot, it will be observed that it is distinguished from the root by not 

 forming in front of the apex a protecting cap. In further contrast with 

 the root, the shoot possesses an uninterrupted epidermis over its entire 



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