PROPAaATlOX BY XODES '2b 



the Howor, certain important properties pertaiiiins' to them, in addition 

 to their ability to multiply and grow as aho\-e inciicated, should reoei\'e 

 attention, in order that later a eom})arison of reproductive metho(1s can 

 be instituted. It is found that if, in the case of many plants, a stem 

 be laid prostrate in the soil, its connection with the parent not destroyed 

 (Fig. 2), its nodes, in addition to producing branches (a), may develop 

 roots (/)) similar in structure and function to those of the parent. If 

 now the phytomers be separated through some portion of the internode, 

 they will heal the wound so produced by the formation of a callus (c), 

 continue to grow independently, and become plants similar to the parent. 

 Such a process, here of artificial production, is of frequent natural 

 occurrence and is called Propagation. It is seen to be, in this case, 

 purely \egctative, and may be defined as the production by vegetative 

 processes of a plant-body growing independently and separately from 

 that from which it was deri\'od. 



Fig. 2 Prop.ig.'ition by layering, a, axillary bud developed iuto a stem; b, adventitious roots; 



c, callus. 



Various other modes of stem-propagation may here be referred to, 

 and it may be remarked that the process is not confined to the node, 

 occurring in exceptional cases from fragments of the internode, root, 

 or even leaves. The pliytomcrs, instead of remaining attached during 

 the rooting process (Layering), may be first separated (Propagating by 

 Cuttings). The cutting, in this case called a Scion, may be inserted 

 (Grafting) or a bud may be so inserted (Budding) under the bark of a 

 living stem, or it may be caused to take root in the soil. Propagation 

 by tubers or parts of them, as in the case of the potato, is identical. 

 It may be remarked, in passing, that in the seed itself nature resorts to 

 a similar method, for the contained embryo consists of one or more 



