354 HORTICULTURE. 



will be more likely to introduce the pollen of the same, or 

 similar species from a distance. 



III. Improvement of varieties or races. The remarks al- 

 ready made, apply to the improvement of the races or varie- 

 ties. A fixed improvement in the quality of the produce of a 

 plant, can be obtained only in two ways ; eiihex accidentally ^ 

 or by the process of muling. 



1. Accidental varieties often spring up, we know not why, 

 but when they occur, they indicate a change in the organ, 

 which is sometimes propagated in the seed. The nectarine 

 may thus have been produced from the peach. 



2. But the most direct means of establishing new breeds or 

 varieties, is by a process called cross-breeding or muling; 

 that is, by selecting the most vigorous plants of two varieties, 

 and putting the pollen of the one upon the stigma of the other. 

 A new variety will thus be produced, which may be perpetu- 

 ated as above described. In this, way, nearly all our varie- 

 ties of squash and mellon are produced; and some of the 

 most gaudy and beautiful flowers which adorn our gardens. 

 There is no end to the different varieties which may be form- 

 ed by this process. 



Sect. 2. Propagation hy Eyes, Cuttings, Grafting and 

 Budding. 



The natural mode of propagating plants, is by means of 

 their seeds ; but, as we have seen, we cannot always rely up- 

 on that mode of continuing the same variety. Hence, propa- 

 gation by other modes has been resorted to, as the most 

 certain means of preserving and continuing any variety de- 

 sired. These modes recommend themselves to our attention 

 by another circumstance ; the time required to procure the 

 fruit from any species is much less, than when the seed is 

 employed. 



Annual plants must be propagated by their seeds, or by their 

 tubers. Biennial and perennial plants, may generally be pro- 



