LEAF-B' DS. 



153 



by the means of their Leaf -buds. If destitute of Leaf-buds, 

 they have no power of multiplication, except fortuitously. 



IV . Leaf- Buns. 



84. Leaf-buds are rudiments of brandies, enclosed within 

 scales, which are imperfectly formed leaves. 



85. Al! the leaf-buds upon the same branch ere constitu- 

 tionally and anatomical!) the same- 



86. They are of two kinds; viz, regular or normal, and adven- 

 titious or latent. (119) 



87. Regular leaf-buds are formed at the axilla? of Leaves. 

 88- They are organs capable of propagating the individual 



from which they originate. 



89. They are at first nourished by the fluid lying in the 

 pith, but finally establish for themselves a communication 

 with the soil bv the woodv matter which they send downwards. 



90. Their force of developement will be in proportion to 

 their nourishment ; and, consequently, when i\ is v\i-hcdto 

 procure a young shoot of unusual vigour, all other shoots in 

 the vi,i iffy are, prevented growing, so as to accumulate for 

 one shoot only all the food that would otherwise have been 

 Consumed by sever., I. 



91. Cutting back to a few eyes is an operation in pruning 

 to produce the same effect, by "directing the sap, as it ascends, 

 into two or three buds only/instead of allowing it to expend 

 itself upon all the others which are cut away. 



92. When leaf-buds grow, they develope in three directions ; 

 the one horizontal, the other upw aid, and the third downward. 



93. The horizontal developement is confined to the cellular 

 system of the bark, pith, and medullary rays. 



94. The upward and downward developements are confined 

 to the woody fibre and vascular tissue. 



9o. In this respect they resemble seeds; from which they 

 differ physiologically in propagating the individual, while 

 seeds can only propagate the species. 



96. When they disarticulate from the stem that bears them, 

 they are called bulbs. 



97. In some plants, a bud, when separated from its stem, 

 will grow and form a new plant if placed in circumstances 

 favourable to the preservation of its vital powers. 



98. But this property seems confined to plants having a 

 firm, woody, perennial stem. 



99. Such buds, when detached from their parent stem, send 

 roots downwards and a stem upwards- 



100. But if the buds are not separated from the plant to 

 which they belong, the matter they send downwards becomes 

 wood and liber, (66J and the stems they send upwards be- 

 come branches. Hence it is said that wood and liber are 

 formed by the roots of leaf-buds, 



