SECT. IV. DECOMPOSITE ORGANS. 253 



the respective examples of the Horse-chesnut and 

 Box, though the growth and induration of the plant 

 are also liable to be affected both by soil and ex- 

 posure. 



Sometimes the one side of a shoot will remain in 

 a state capable of extension longer than the other ; 

 and hence the tree is liable to become deformed. 

 But gardeners correct or prevent the deformity by 

 making a number of oblique incisions in the bark 

 of the shoot on the side to which it is inclined, 

 which, by occasioning an irruption of the cellular 

 tissue, forces it back again to an erect posture. 



At the junction of the root and stem, which I Thecollar. 

 have denominated the collar, there is generally to 

 be observed a sort of irregular and circular pro- 

 tuberance, similar to that which is occasioned by the 

 operation of grafting. This is owing first, to 

 its being the point of the insertion of the seed 

 leaves secondly, to its being the point in which 

 the divisions of the roots often originate, causing a 

 deflection of the longitudinal fibres and lastly, by 

 the different degrees of augmentation which take 

 place in the root and stern, the latter augmenting 

 more than the former, and consequently occasion- 

 ing a bulge. 



Such is the mode of the growth and develope- Growth of 

 ment of the trunk of perennial and woody plants, O fp a i mg . 

 to which there exists indeed a striking exception in 

 the growth of the trunk of Palms. Their internal 

 structure has been already taken notice of as pre- 



