7 



* 

 ^ 



tain hundreds of these granules, when they arc completely 

 filled with the nearly spherical masses. 



The relative position of the starch varies greatly with dif- 

 ferent buds, especially in widely separated species of trees 

 and shrubs, but in those that are well matured, upon the same 

 plant, there is a fair degree of constancy. 



At this point it is necessary to state that there arc two 

 classes of terminal buds, so called, among ligneous plants, 

 with some gradations between them, not a little confusing. 

 There are those which are characteristic of plants, with a well- 

 defined habit of growth, that is, those that lengthen their 

 shoots for a definite period, as in the horse-chestnut, for ex- 

 ample, and then spend the balance of the growing season in 

 forming a large terminal bud, and supplying it with nourish- 

 ing food for the next year's development. On the other hand, 

 there is a large group of trees and shrubs, and especially 

 brambles, that grow on indefinitely, produce no plump, ter- 

 minal bud for winter, usually kill back, and therefore must 

 start the farther elongation of the twig from some lateral bud 

 perhaps a foot or more back from the end of the stem. It 

 is needless to say that the remarks to follow obtain only 

 with the first class, and the consideration of the second will 

 appear later, because less simple. 



In order to make a careful, microscopic study of the cell 

 elements of a terminal bud, it is necessary to secure several 

 thin sections with a sharp razor, made in various directions 

 through the bud. One of the most satisfactory is made length- 

 wise through the middle of the bud, and from this the posi- 

 tion of the food-elements, after a little experience, can be 

 determined with a fair degree of accuracy. This is said, not 

 to discourage the making of horizontal sections, which are 

 necessary for the demonstration of some important points, but 

 to facilitate the work of those who may choose to extend the 

 investiijation herein' outlined. 



Fiiiure I shows such a section throuc^h the terminal bud of 

 an apple-twig, made in February, 189O, and therefore during 

 a remarkably warm winter. The feature to be first observed 

 is the dark column in the lower center (a) of the figure. This 

 is the pith of the subadjacent stem, the cells of which are 



