BOTANY. 351 



degree unoccupied by our botanical writers. The last great group, in refer- 

 ence to the term of life, denominated Perennial, or, in the phrase of Lindk-y, 

 Caulocarpous, are those " whose stem endures many years, constantly bear- 

 ing flowers and fruits, as trees and shrubs." In this group the efforts of life 

 are of two kinds the production of buds of extension and those of fruit. 

 The fruit, flower, or seed buds, resemble in some degree, in their function, an 

 annual or monocarpous plant. Death follows the reproductive process. It 

 is otherwise with the extension buds. Both, however, are greatly under the 

 influence of external circumstances. An abundant supply of nourishment 

 makes a tree generate extension buds almost exclusively ; whereas a scanty 

 supply of food promotes the reproductive efforts, and fruit buds predomi- 

 nate, a process the reverse of that which prevails in the animal kingdom, 

 where it has long been alleged " sine Cerere et Libero friget Venus "(Hor- 

 ace). By many vegetable physiologists it has been supposed that the life of 

 a tree is confined to its buds; that the stem is a sort of dead soil, or, rather, 

 support; and farther, that the bud, when it evolves in spring, acts like a seed, 

 sending downwards certain vessels to act as roots, and another set upwards, 

 for extension of the individual and the formation of new buds for devel- 

 opment in the following season. In this view of the matter, the ti'ee, with 

 the exception of the buds, is an aggregation of dead cells. The authors 

 who have adopted this notion have been chiefly influenced by considering 

 the poAver which buds possess of developing themselves in certain circum- 

 stances, even when detached from the stem, as in the act of budding, and 

 even by the more ordinary process of extension by slips. To this view of 

 vegetable life there have ever appeared to me to be grave objections, which, 

 to save the time, I shall state very briefly. 1. I shall not here dwell on the 

 fact, that, by particular processes, the leaves, stem, and roots can be made to 

 produce buds, or the parts supposed only subservient to vitality can exercise 

 living functions from vital centres, nor on the action of poisons. 2. When a 

 tree is grafted say a cultivated apple on a crab stock the buds of the 

 graft may extend into a lofty tree, and yet its downward roots, although be- 

 coming continuous, never embracing the stock and reaching the soil. The 

 stock remains the same in its bark, wood, and pith, and, after many years, 

 if it produces buds and suckers, these invariably retain the characters of 

 their crab original. The practice of dwarfing fruit trees would prove a fail- 

 ure if the buds contained the whole life of a tree. A slow-growing stock is 

 selected, on which is inserted a fast-growing graft, or one inclined to gen- 

 erate extension rather than fruit buds. If the buds of the graft annually 

 sent down their roots to the ground, the influence of the stock should cease 

 by the second year, an event which does not occur. 3. The difference 

 between summer and winter felled wood is equally hostile to the notion that 

 the life of a tree is limited in winter to its buds. The cells of the newer lay- 

 ers of wood are storehouses of nourishment : the sap, when beginning its 

 ascent, is nearly pure water; as it ascends it becomes more and more loaded 

 with the contents of the cells through which it has travelled, and the buds 

 are thus supplied with nourishment by the living agency of the former year, 

 which made the buds and provided for its development. Hence the com- 

 parative lightness of timber felled after the bud has evolved its leaves. The 

 stem of a tree is the common support of all the organs, the receptacle of the 

 peculiar juices, and the storehouse of nourishment. The buds evolve sim- 

 ultaneously or successively according to a law of a symmetry and coopera- 



