1 02 ORGANOGRAPHY. 



by the development of tissue at the point where the branch 

 springs from the axis. 



From the above circumstances, it follows that a bud resembles 

 in its functions the embryo from which growth first commenced, 

 and it has been thus termed a fixed embryo. There is this 

 difference however between them, — a bud continues the in- 

 dividual, while the embryo continues the species, A stem is 

 therefore really made up of a number of similar parts or buds, 

 called phytons, which are developed in succession, one upon the 

 summit of the other. Hence, by the development of terminal 

 buds the stem increases in height ; and by those situated late- 

 rally branches are produced. A tree may thus be considered as 

 a compound body, formed of a series of individuals which mu- 

 tually assist each other, and benefit the whole mass to which 

 they belong. In exogenous trees, which form lateral or axillary 

 buds, the destruction of a few branches is of no consequence, as 

 they are soon replaced; but in Palms, and most other en- 

 dogenous trees, and also in those of acrogenous growth which 

 develope only from terminal buds, the destruction of these under 

 ordinary circumstances, as we have seen, leads to their death. 



The buds or similar parts, of which a tree has thus been shown 

 to be made up, are also capable of being separated fi'om their 

 parent and attached to another individual of the same, or Qxan 

 of one of a nearly allied species. The operati'. ns of Budding, 

 Grafting, &c., depend for their success upon this circumstance. 

 In some plants, buds naturally separate from their parents, and 

 produce new individuals. These operations are of great impor- 

 tance in horticulture, because all plants raised by such means 

 propagate the individual peculiarities of their parents, which is 

 }iot the case with those raised from seed, which have merely a 

 specific identity. 



Ramification. — In the same Avay as branches are produced 

 from buds placed on the primary axis or stem, so in like manner 

 from Ihe axils of the leaves other buds and branches are 

 formed ; these again will form a third scries, to which will 

 succeed a fourth, fifth, &c. In practice, the main divisions of 

 the primary axis or stem are called branches (rami), while the 

 smaller divisions of these are commonly termed twigs (ramuli). 

 The general arrangement and modifications to which these arc 

 liable are commonly described under the name oi ramification. 



All lateral or axillary buds which are develojied in the axil 

 of leaves arc called regular or normal, and their arrangement in 

 such cases is necessarily the same as that of the leaves Again, 

 as branches arc formed from huds thus phu-cd, it should follow 

 that their arrangement should also corresiiond to that of the 

 leaves. This corresponding symmetry, however, between the 

 arrangement of the branches and leaves is interfered with from 

 various causes. In the first place esjiecially, by many of the 



