26 



LABOBATORY STUDIES OF BUDS 



Add the ages of all the existing buds, individually. Then divide 

 this total by the whole number of buds. This gives the average age 

 of the buds. How old is the oldest bud on the branch ? Cut some of 

 the oldest ones open. Should you judge them to be still capable of 

 development, in case of need? 



Record in your notes all numbers and ages. 



Exercise XIII. Comparative Vigor of Development 



Select a lateral branch of the Maple provided, showing a few years' 

 growth. Hold the branch in the position in which it grew. Certain 

 of the leaf scars now look upward, part of them to right or left (hori- 

 zontally), and part toward the earth. That is, there are two sets, 

 the vertical (above and below) and the horizontal. In each set count 

 the whole number of pairs of leaf scars ; also the number (pairs) 

 where the buds have made some growth. 



Record in a table like the following : — 



Measure roughly the combined length of all the horizontal twigs 

 developed from lateral buds. Combined length of vertical twigs. 

 Compare the numbers obtained thus : — 



Total length of all horizontal twigs 



Total length of all vertical twigs 



Count the whole number of present winter buds on all the twigs of 

 each set separately. This gives a hint as to their comparative vigor. 

 Record thus : — 



Buds on horizontal twigs 

 Buds on vertical twigs . 



Is there any advantage to the tree in the superior development of 

 one system over the other? 



This exercise is intended to bring out two facts: first, that certain 

 buds are more likely to develop than others ; second, that certain buds 

 develop more vigorously than others. The exercise is not intended to 

 teach — what would not be universally true — that the horizontally 

 directed buds, for example, are always more vigorous than vertically 

 directed buds ; or vice versa. 



