CHAPTER III 

 PROPAGATION OF PLANTS 



Plants may be propagated by spores, by seeds, and 

 by division. The most important methods of propaga- 

 tion on the farm are by spores, seeds, and by several 

 methods of division, such as creeping stems and root- 

 stocks, tubers, cuttings, buds and grafts. Nearly all 

 economic plants are propagated by means of seeds. 



34. Spores differ from seeds in that they do not con- 

 tain an embryo, or young plant. They are usually one- 

 celled, or few-celled and microscopic. Only the lower 

 orders of plants form spores. The flowering plants form 

 seeds. Spores may be foVmed sexually or asexually. The 

 rusty margins on the underside of fern leaves contain 

 spores. The dust of a puff-ball is composed of countless 

 spores. Corn smut, oat smut, oat rust, are 

 masses of spores. 



This method of propagation is not of great 

 FIG. is. direct importance in agriculture, because only a 

 few of these plants are of use to us. But spores 



highly 



magnified, are of great importance when we come to con- 

 sider plant diseases, for nearly all such diseases are caused 

 by plants that reproduce by spores. 



35. Creeping Stems and Rootstocks. The branches of 

 white clover take root, and so form new plants (Fig. 14). 

 This enables it to persist many years in pastures where 

 red clover is exterminated 



(36) 



