190 Principles of Plant Culture. 



regarded as simply a continuation of the growth of the 

 parent in a new location, and generally closely resem- 

 bles the parent. 



342. Propagation by Seeds is commonly practiced 

 with annual and biennial plants and with perennials in 

 which the reproduction of the exact parental form is 

 unimportant, as in the cereals, forest trees and seedlings 

 intended for grafting. This method is also used when 

 variation in the progeny is desired, as in developing 

 new varieties (438 b). 



343. Propagation by Division of the plant is used 

 when it is desired to reproduce the exact parental form, 

 as in fruit- and the finer ornamental trees, many flower- 

 ing plants, etc. ; in certain plants that are' more readily 

 multiplied by division than by seeds, as mint and many 

 other perennial herbs; and in other plants that rarely 

 or never produce seed, as the horse-radish, sugar cane, 

 banana, etc. 



A PROPAGATION BY SEEDS. 



344. This is the most common method of propagating 

 plants. It seemed appropriate to give nearly all of the 

 needed directions for planting seeds in the first two sec- 

 tions of Chapter II. We add, therefore, only a few 

 general rules deduced from the principles there stated. 



a The soil in which the seeds are to be planted should 

 be thoroughly crumbled, because the seeds must have 

 access to the oxygen of the air, or they cannot germi- 

 nate (31). 



b The well-crumbled soil should be compactly pressed 

 about the seeds, because the seeds cannot absorb moist- 



