CHAPTER IV 

 STEM AND SHOOT 



40 



39 



DEFINITE AND INDEFINITE GROWTH IN LENGTH. 



An ordinary stem of a flowering plant elongates solely by 

 means of growth at its apex. The apex may continue to grow 

 for a long period, so that the stem will bear many leaves and 

 lateral buds ; such a stem is said to be unlimited or indefinite. 

 in its growth. On the other hand, the 

 apex may soon cease to grow, so that the 

 stem attains only a limited or definite 

 length. The Scotch Pine (fig. 62) has 

 shoots which exhibit both these methods 

 of growth. The main trunk and con- 

 spicuous branches are of indefinite growth, 

 and bear leaves only in the form of scales ; 

 they constitute the so-called long-shoots. 

 In the axils of most of the scales on the 

 long-shoots there arise lateral dwarf-shoots 

 (fig. 39). Each dwarf-shoot consists of 

 a short definite stem, bearing just below 

 its apex two needle-like green foliage- 

 leaves (/), and below these a number of 

 scale-leaves {s) : the apex {a) of the stem 

 lies between the two needles (fig. 40). 



Stem or axes of different orders (fig. 



41)- — A stem is an axis bearing leaves. 



This definition gives us no means of 



stating simply whether the stem be a 



main stem or a lateral one : hence it is 



advisable to adopt some terms by which 



we can explain to which stem we are 



alluding. The main stem (i.) is described as an axis (stem) of 



the first order, or. as the primary axis. A lateral axis (11.) 



24 



Fig. 3^. — A dwarf-shoot 

 of Pine, in axil of scale (sc). 



Fig. 40. — Vertical section 

 of ditto. 



