THE PROPAGATION OF PLANTS 189 



344. Methods of propagation by divisions. Two 



methods of propagation by division may be distinguished, 

 viz., by parts intact and by detached parts. In the first, 

 the part selected for propagation is not separated from 

 the parent until the organs needed to make it self-sup- 

 porting are formed ; or if a cion (386) , until it has united 

 to the part on which it is intended to grow. In the second 

 method, the part intended for propagation is severed from 

 the parent at the outset and placed under conditions favor- 

 ing the formation of the organs needed to make it self- 

 supporting; or if a cion, favoring its union with the 

 stock (383). 



345. Propagation by parts intact. This method is 

 applicable to many plants and has the advantages of 

 being reliable and requiring little skill. The part selected 

 for propagation, being nourished by the parent until it 

 forms the needful organs, is able to endure unfavorable 

 conditions that would prove fatal in most other methods 

 of propagation. This method includes four divisions, 

 viz., propagation by suckers (346), by stolons (347), 

 by layers (348), and by approach grafting (399). In 

 the first two, the propagation is performed by the parent 

 plant without other aid than the maintenance of a well- 

 aerated, moist and clean soil that stimulates the pro- 

 duction of the needed organs, which in these cases are 

 roots. 



346. Propagation by suckers. Suckers are shoots 

 that originate from roots or underground stems and 

 grow upward, forming young plants about the parent, 

 as in the blackberry, plum, choke-cherry and the like. 

 The propagation consists in simply cutting off the root 

 or underground stem whence the sucker proceeds, and 

 transplanting the latter. 



