FROM SIMPLE LEAVES. 125 



diminishes with each succeeding generation of shoots, until 

 at length it approaches its limit in buds, which unfold year 

 after year into mere clusters of leaves. The bud traces on 

 such shoots follow each other in close order, the leaf scars 

 are reduced in size, and finally the terminal bud becomes 

 abortive, and all further growth in that direction is necessarily 

 arrested. There is also a well-marked remission of growth 

 in the direction of the main axis of the branch. For after a 

 certain point of time in the development of the main axis, the 

 growth it makes each year becomes less and less ; and this is 

 accompanied by a loss of ramifying power in the families of 

 shoots which it developes laterally, so that there is an exact 

 correspondence subsisting between the loss of vegetative 

 power in the branches of the upper region of the principal 

 axis, and in the second and third generation of shoots devel- 

 oped by the branches of its lower region. 



The same laws of remission of growth from one generation 

 to another manifest themselves in the structure of herbaceous 

 plants, which branch or repeat themselves in the axilla of their 

 leaves, one, two, or even three generations of branches being 

 developed during the same season. If this process of ramifi- 

 cation is examined in the common St. John's Wort (Hypericum 

 perforatum), or any other branching herbaceous plant, it will 

 be evident that these successive side-productions are only 

 repetitions of the whole plant on a constantly diminishing 

 scale of magnitude, and that there is a beautiful symmetry 

 apparent throughout the whole of them. For the branches 

 given off from the axilla of the opposite pairs of leaves which 

 clothe the stem of the primary axis, not only meet the axis 

 at the same angle, but the lower branches are less developed 

 than the upper branches, whose leaves are carried forward to 

 the highest stage of vegetative metamorphoses and terminate 

 in flowers. Hence there is only one generation of branches 

 developed from the axillae of the lower leaves of the primary 

 axis, whilst the leaves situated toward its summit develop two 

 generations ; and as each branch terminates in a flower, its 

 growth necessarily ceases. Herbaceous plants therefore follow 

 precisely the same laws of ramification as the trees which 



