THE STORY OF SEEDS 



253 



FIG. 94. Small plants produced 

 by the fern spores; one of them 

 is producing a new fern- pi ant. 

 After J. M. COULTER. 



much stored-up food. Unless they fall on a favorable place 

 very soon after they are set free in the world, the spores 

 of common ferns soon perish. Seeds, however, may live 

 for many years. 



The spores of ferns do not produce fern-plants. They 

 produce a little flat green structure that looks like a little 

 liverwort (see Fig. 94). This 

 structure produces sperms and 

 eggs. The sperm swims to the 

 egg, and the fertilized egg pro- 

 duces the fern-plant. 



Now let us see how this fourth 

 step (fern) is different from the 

 third step (moss and liverwort). 

 In mosses the sperms and eggs 

 are produced at the top of the 

 little baby plants, while the spores are produced on struc- 

 tures that have no leaves (see Fig. 92). But in ferns the 

 spores are on the leaves, while the sperms and eggs are pro- 

 duced by a small structure that 

 has no leaves. These two things 

 have been reversed. You see 

 that in plant life there are two 

 generations the spore-bearing 

 generation and the sperm-and- 

 egg-bearing generation. In the 

 ferns it is the leafy generation 

 that bears spores, and this is also 

 true of seed-plants. 



Now we are ready for the fifth 

 step. This step is illustrated by a very graceful plant that 

 is common in greenhouses. This plant is a distant relation 



FIG. 95. Diagram of a flower. 5 

 is a stamen; is an ovary. 



