196 PRINCIPLES OF PLANT CULTURE 



and reproduce the needed organs; or if a cion (386), to 

 unite by growth to the part with which it is placed in 

 contact. 



In propagation by sections of the plant we must, of 

 necessity, wound the plant tissues in securing the parts 

 for propagation. Since it is always desirable that the 

 wound should heal promptly (72), it is important that the 

 cutting tools used should have sharp and smooth edges. 



As here considered, propagation by sections of the 

 plant includes two methods, differing materially in 

 their requirements and in the manner of development 

 of the plants, viz., propagation by cuttings and by graft- 

 ing. 



358. Propagation by cuttings. — A cutting is a detached 

 part of a plant, intended to be placed in the soil or some 

 other medium for the purpose of developing roots. It may 

 be in an active or a dormant state (13) and may or may not 

 contain a growing point (66) . Before the cutting can be- 

 come a plant, it must develop the essential part or parts 

 of the plant that it lacks, i.e., the stem and the leaves or 

 the root, or all these members. Cuttings of the stem are 

 usually planted with their proximal end (115) in the soil, 

 and their distal end in the air. Root cuttings are gen- 

 erally covered in the soil. 



359. Ease of propagation by cuttings. — Nearly all 

 plants may be propagated by cuttings from one or another 

 of their parts. The ease with which plants may be multi- 

 plied in this way varies greatly in different species (21), 

 and even in different varieties of the same species. The 

 appearance of a plant does not always indicate the facility 

 with which it may be grown from cuttings; the only 

 sure way to ascertain this is by trial. 



Climate exerts a marked influence upon the tendency 



