40 BUBS. 



enabled to divide individual trees indefinitely by grafting, bud- 

 ding, and by layers. The Leaf-Bud may be defined to be the 

 rudiment of a branch, which, in its development, it always pro- 

 duces. Buds are distinguished by different names, according to 

 the point from which they spring. If they originate in the 

 axils of the leaves, they are called regular ; if from any other 

 part of the plant, they are called adventitious. 



71. The regular leaf-bud has its origin in the pith and 

 medullary sheath. The earliest view of the regular leaf-bud we 

 can obtain by dissection, is in the form of an exceedingly minute 

 green body, surrounded by a nearly transparent cellular sub- 

 stance situated in the stem immediately below the axil of the 

 leaf. If we examine the buds of the same tree through the 

 season, we shall find that the cellular part becomes opake, and 

 its place is occupied by scales, and the central part increases, and 

 becomes the apex of the bud. By a longitudinal section of 

 the bud and stem at this stage, the rudiment of a branch may 

 be distinctly traced under the microscope ; the greenish medul- 

 lary sheath and pith being separated by a white deposit from 

 the greenish portion, which is to become the bark. There is a 

 bud on the extremity of the branch called the terminal bud, 

 similarly constituted to the axillary ones above described. The 

 scales by which the rudimentary branch is inclosed, appear to be 

 formed for this express purpose; but they are indurated, par- 

 tially developed leaves, as one may readily convince himself by 

 taking, in the spring, the bud of the Buckeye, when he will find 

 the outer scale hard, dry, and with a uniform margin ; but by 

 removing one after another, he will find them gradually become 

 soft, delicate, and lobed, being the miniature leaves of the plant. 

 The leaves first developed are sacrificed for the protection of the 

 remainder during the cold of winter. Plants of the torrid zone 

 and annuals have no such covering, as, from the nature of the 

 case, they need none ; the one growing in a climate where the 

 cold of winter is not felt, the other existing only through a pe- 

 riod favorable for vegetation. The buds are not only inclosed 

 in scales, but they are often provided with means which render 

 their covering much more effectual in resisting outward influ- 

 ences. A resin is not unfrequently secreted by which the scales 

 are attached to each other, and rendered proof against the action 

 of water, as in the Balm of Gilead, the Poplars, &c. In oth- 

 ers a coating of soft down is produced on the surface of the 



What is a leaf-bud ? When regular ? When adventitious? — 71. What 

 is the origin of the regular leaf-bud? Explain its growth. What of the 

 scales of the bud ? Do annual plants have scales ? Do plants of the torrid 

 zone ? Why ! What other means of protection do buds have ? 



