PROPAGATION. 203 



the flowers and seed, or of the appendages of the 

 seed vessels. These variations, if considered improve- 

 ments, are more or less valued, and consequently 

 become interesting objects of the cultivator's care. 

 Many variations which take place among herbs are 

 perpetuated by their seed ; but among improved fruits 

 and flowers their seed, as has been before noticed, 

 does not convey those variations in quality, form, and 

 colour for which they are valued ; and consequently 

 the cultivator is compelled to have recourse to other 

 expedients to preserve and continue the excellencies 

 he regards. 



Varieties are propagated by cuttings, layers, and 

 by grafting and budding. All these practices have 

 for their object the forming a new plant of the im- 

 proved variety by placing a part of it in the ground 

 to take root, or by grafting or budding it upon a 

 kindred stock. 



The methods of performing these expedients being 

 so well known need not be described here. But as 

 their practicability depends on the constitutional 

 powers and organisation of the plants so propagated, 

 these properties require to be noticed. 



Cuttings. All exogenous trees and shrubs may 

 be propagated by cuttings, whether the stems be 

 jointed or simple. Some kinds form roots readily 

 from any part of the stem, others with more diffi- 

 culty, owing perhaps to the resinous or some other 

 quality in the sap, which soon becomes corrupt when 

 placed, as cuttings usually are, in the soil. 



