92 



ESSENTIALS OF BOTANY 



" spurs " as are shown in Fig. 52 are of little use in the 

 permanent growth of the tr^e, and poplars, elms, soft 

 maples, and other trees shed the 

 oldest of these every year. What- 

 ever the amount of this growth, it 

 is but the lengthening out and 

 development of the bud, 

 which may be regarded as 

 an undeveloped stem or 

 branch, with its internodes 

 so shortened that succes- 

 sive leaves seem almost to 



Fii.. 54. A Slowly Grovfn 

 ,Twig of Cherry, Three 

 Inches Long and about 

 Ten Years Old. 



The pointed bud, I, is a leaf- 

 bud; the more obtuse 

 accessory buds, /, /, are 

 flower-buds. 



spring from the same point. 

 In Figs. 52, 53 the com- 

 plete history of a fruit-spur 

 of the pear is shown, from 

 the leaf-bud which pro- 

 duced it to the pear which 

 it bears. 



Fig. 55. 



B, a twig of European elm ; A, a longi- 

 tudinal section of the buds of B (con- 

 siderably magnified), ax, the axis of 

 the bud which will elongate into a 

 shoot ; sc, leaf-scars. 



110. Vernation. — ^^ Procure a considerable number of buds which 

 are just about to burst and others which have begun to open. Cut 

 each across with a razor or very sharp scalpel ; examine first with 



