150 PROPAGATION OF PLANTS. 



the buds on the young stems ; and it must be apparent 

 that there will be less liability of water lodging within 

 the stem and causing decay if the .cutting is severed just 

 below the joint than at any other point. 



The roots produced on a cutting are sjrrjposed^ to be 

 formed from the sup or assimilated juices of the plant, 

 deposited mainly between the bark and wood ; but the 

 stems and branches of some kinds of woody plants, hav- 

 ing a large pith or hollow stem, will throw out roots 

 from the inner portion, but this does not disprove the 

 general theory of circulation of the sap, or that roots 

 emanate only from the assimilated sap or nascent matter ; 

 because it is not impossible, nor contrary to" the general 

 principles of vegetable physiology, that a portion of the 

 true sap of exogenous plants may not pass from the outer 

 to the inner surface of the stems of young wood, at least 

 when placed under artificial conditions. 



There are some authors who contend that a bud, either 

 latent or developed, is essential on a branch to enable it 

 to produce roots ; in other words, roots always proceed 

 directly from a bud ; and if a cutting is severed at a dis- 

 tance below a bud, the roots start from the lowermost 

 one and push their way down under the bark and out at 

 the end, establishing a communication with the source 

 from which they are to derive their future nourishment. 

 It was also claimed by some of the old vegetable physiol- 

 ogists, that in the same manner all the buds below the 

 surface of the soil, which do not grow upright and form 

 branches, produce roots by going down, overlapping and 

 intermingling with those produced below them. 



The erroneous theory of roots emanating only from 

 buds doubtless originated from the fact that many kinds 

 grow more readily from cuttings if they are cut off close 

 to the base of a bud, as before stated, thereby strength- 

 ening the belief that at this point was located the mate- 

 rials from which roots are formed. To ascertain whether 



