ORGAXS OF NUTEITION. 



•95 





purpose, is proved not only by their position with regard to the 

 true leaves, but also from the gradual transitional states, which 

 may be frequently traced from them to the ordinary leaves of the 

 bud. 



As soon as the laminae of the leaves in the bud have acquired 

 a certain size, they become variously folded or rolled on one 

 another, by which they adapt themselves to its form and small 

 space. This arrangement of the leaves in the bud is called 

 mrnatio7i or jpnefoliation. There are various modifications of 

 this, each of which is distinguished by a particular name; these 

 will be described hereafter. 



The bud, as we have seen, contains all the elements of a stem 

 or branch (/^. 184); in fact, it is really the first stage in the 

 development of these parts, the axis being here so short that the 

 rudimentary leaves are closely packed together, and thus over- 

 lap each other {fig. 185, c). When growth commences in the 

 spring, or whenever vegetation is reanimated, the internodes 

 between the leaves become developed, and these therefore become 

 separated from each other {fig. 186, c, c, c), and thus the stem in- 

 creases in length, or a branch is formed. In other words, the 

 leaves, c, which in a bud state overlap each other and surround 

 a growing point or axis, by the elongation of the internodes of 

 that axis become separated and dispersed over a branch or an 

 elongation of the stem, much in the same way as the joints of 

 a telescope become separated from each other by lengths of tube 

 when it is drawn out. The branch, therefore, like the bud 



Fig. 185. Fig. 186. 



Fig. 185. A shoot one year 

 old of the Horsechestnut, 

 •with terminal bud. a. Scar 

 produced by the falling off 

 of the bud-scales of the pre- 

 vious year ; &,b. Scars pro- 

 duced by the falling off of 

 the petioles of the leaves of 

 thepresentyear.with buds, 



c. in their axils. Fig.l86. 



Diagram to illustrate the 

 growth of the shoot from 

 the bud. c,c,c. The nodes 

 ■where the leaves are situ- 

 ated. d,d. The internodes 

 developed between them. 



from which it is formed, necessarily contains the same parts as 

 the axis upon v/hich it is placed, and these parts are also conti- 

 nuous with that axis, with the exception of the pith, which, 

 although originally continuous in the bud state, ultimately be- 

 comes separated by the development of tissue at the point where 

 the branch springs from the axis. 



