40 THE VEGETATIVE SHOOT 



they begin to develop that the stouter and blunter characters of 

 the fruit-buds show themselves. 



Their position upon the shoots is a great aid in distinguishing 

 the two classes of buds (see pp. 44-50). 



8. Branching of Stems. — The axis or stem of the primary 

 shoot of plant is at first single, and may continue to grow 

 as a simple straight structure. Usually, however, after a time, 

 branches or secondary axes arise upon it, and these in all cases 

 proceed from buds. In Fig. 11, of the primary bud of a bean,' 

 secondary lateral buds are seen in the axils of the leaves of b' 

 and b : these are flower-buds, and consequently do not produce 

 long leafy shoots ; but secondary axes bearing green leaves fre- 

 quently occur in the bean, and are generally produced from 

 buds in the axils of the cotyledons as at g (Fig. 1 1). 



In many plants the buds in the axils of each leaf of the 

 primary stem develop into leafy shoots, and upon the latter 

 branches may again arise in a similar manner. The total 

 number of stems bearing leaves may thus become very large 

 on a single plant. In the best fodder crops, where large yield 

 is always a desirable feature, branching is exhibited in high 

 degree, and the same may be observed in trees of all kinds, 

 and many weeds, such as groundsel and chickweed. 



9. The main stem of a plant is spoken of as a primary axis, or 

 axis of the first order, the branches upon it being secondary axes, 

 or axes of the second order, those borne by the latter tertiary 

 axes, and so on. For purposes of convenience in description, 

 any axis may be considered a main one, its brarjches then 

 being secondary axes. 



10. When a stem continues to grow at its apex, for a long 

 time it is spoken of as indefinite in growth : the branches upon 

 it are usually many in number, and smaller than the main stem. 

 This form of branching is spoken of as racemose (a. Fig. 15). 



In many plants the terminal bud produces a flower or a 

 collection of flowers, and the main axis then ceases to elongate : 



