AND SUBORDINATION. 83 



by the labors of individual phytons or plants, called leaves. 

 One generation of these phytons perishes every year, but not 

 before each individual of the generation has formed a bud, 

 which remains when the leaf falls, through the winter months, 

 the embryo, leaves and stem which it contains developing on 

 the return of the next vegetative season. If ; therefore, the 

 leaves are regarded as phytons or individual plants, the 

 series of buds which they produce and from which come forth, 

 when circumstances are favorable, new families of leaves, may 

 be correctly regarded as a new generation ; and if we consider 

 the first set of leaves as the parent, or the entire shoot, built up 

 by them, as the mother shoot, the first set of buds produced by 

 them which unfold to shoots and leaves, may be called the daugh- 

 ter shoots or the first generation, and the second set of buds 

 generated by the leaves of the daughter shoots, the second 

 generation, &c. 



Now if all leaves produced buds the first year, and if all 

 buds, thus produced, unfolded to shoots and leaves the- second 

 year, then the number of generations of shoots would exactly 

 correspond with the number of years during which the tree had 

 lived, and we should have an easy but simple method of deter- 

 mining its age. But in reality it is not so, because in the 

 development of the main axis of a branch, often single or 

 numerous seasons occur, during which the growth is greatly 

 retarded, and only such leaves are produced whose axilla 

 remain unfruitful, whilst the growth of the side shoots is 

 still more retarded, and they, for the same reason, consequently 

 remain unbranched. Hence, the greatest difference predomi- 

 nates between the number of generations of shoots on a branch 

 and its age. Compare in this respect the growth of the first 

 side-shoot in Fig. L, page 31, with that of the whole branch, 

 estimating, in both instances, from the bud-traces marked, 53. 

 The age of both shoot and branch is the same, five years ; yet 

 how great the difference in the extent to which development has 

 been carried. In five years there has been no side production 

 from the shoot, with the exception of a single bud, and its entire 

 length is only four inches and six lines, whilst in the same time 

 the primary axis has grown twenty-three inches and three lines, 



