90 



THE planter's GUIDE. 



organs. It is the part of the tree in which its bulk and 

 strength principally reside, and has been represented bj 

 Linnseus as the caudex ascendens, or root above ground — 

 an illustration, as Keith truly observes, more fanciful than 

 philosophical.'" 



The stems of trees are augmented in width by an annual 

 layer, and in length by an annual shoot springing from 

 the terminating bud. The development of the shoot 

 from the stem is not effected in the same manner as that 

 of the root, by additions to the extremity only, but by 

 the introsusception of additional particles throughout its 

 whole extent, at least in its soft and succulent state. 

 The extension of the shoot, as Du Hamel justly remarks, 

 is inversely as its induration — rapid while it remains her- 

 baceous, but slow as it is converted into wood. Hence 

 moisture and shade are the circumstances of all others 

 the most favourable to elongation, because they prevent 

 induration, or retard it. f In close and confined planta- 

 tions, therefore, where the external conditions of air and 

 light are imperfectly supplied, the roots are correlatively 

 proportional to the system of ramification. Trees so cir- 

 cumstanced push upwards to the light ; and from the 

 warmth which their situation affords, their stems being 

 thin and slender in proportion to their height, they are 

 destitute of strength to resist the winds. The natural 

 consequence is, that their roots are extremely apt to be 

 shaken and displaced in the ground, and prevented from 

 seeking proper food for the branches and other parts of 

 the tree. 



Now it is obvious that it is these very properties which 

 are the least adapted to removal. Nothing but a stem 



* Physiolog. Bot. vol. i. p. 43. 



t Ibid. vol. ii. pp. 251, 252. Kieser, Organ, des Plantes, p. 164; also pp. 166-168. 



