OF TRANSPLANTING. 285 



not mean that it is always lengthening itself in the 

 form of new branches, for this happens periodically 

 only in evergreens, and is usually confined to the 

 spring; but that its circulation, perspiration, assimi- 

 lation, and production of roots are incessant. Such 

 being the case, an evergreen, when transplanted, is 

 liable to the same risks as deciduous plants in full 

 leaf, with one essential difference. The leaves of ever- 

 greens are provided with a thick hard epidermis (61), 

 which, is tender and readily permeable to aqueous ex- 

 halations only when quite young, a,nd which becomes 

 very firm and tough by the arrival of winter, whence 

 the rigidity always observable in the foliage of ever- 

 green trees and shrubs. Such a coating as this is 

 capable, in a much less degree than one of a thinner 

 texture, such as we find upon deciduous plants, of 

 parting with aqueous vapour; and moreover its 

 stomates (61) are few, small, comparatively inactive, 

 and chiefly confined to the under side, where they are 

 less exposed to dryness than if they were on the upper 

 side also. But although evergreens, from their struc- 

 ture, are not liable to be affected by the same external 

 circumstances as deciduous plants, in the same de- 

 gree ; and although, therefore, transplanting an ever- 

 green in leaf is not the same thing as transplanting a 

 deciduous tree in the same condition, yet it must be 

 obvious that the great extent of perspiring surface 

 „ upon the one, however low its action, constitutes 

 much difficulty, superadded to whatever difficulty 

 there may be in the other case. Hence we are irre- 

 sistibly driven to the conclusion, that whatever care 



