30 



REPRODUCTION 



disturbance breaks them off and sets them free. The 

 spores of the various molds and fungi that live in the air 

 and on solids are without any power of self motion. On 

 the other hand, most of the spores of the lower algae, 

 which live in water, have cilia and can make very definite 

 and interesting motions through the water. 



Figure 9. The formation of spores by wheat-rust. This 

 parasite is growing inside a leaf of its host, and is discharg- 

 ing its spores from the under surface of the leaf. Ftvm 

 Coulter's Plant Life and Plant Uses. 



In some plants only one spore may be formed at a 

 place; in others they may run into the thousands. Spores 

 even in the same plant may differ much in size, depending 

 on the way they are formed and the period of 

 development to which they belong. 



5. Kinds of Plants That Bear Spores. For a long time 

 the plant kingdom was divided into those plants that 

 reproduce by means of spores, and those that reproduce 



