262 



ELEMENTARY SCIENCE 



Relatives of the ferns are the club-mosses, which perhaps 

 you have seen (see Fig. 102). Other relatives are the horse- 

 tails, which I know you have seen. They are curious 



leafless plants, and 

 when they are 

 pointed out to you, 

 you will always rec- 

 ognize them (see 

 Fig. 103). 



4. The Seed-Plants. 

 These are the 

 plants that inhabit 

 the highest story. 

 They are woody, but 

 they also produce 

 seeds. The story of 

 the seed is given in 

 another chapter, and 

 you know some- 

 thing about its struc- 

 ture. The seed- 

 plants are the most 



successful plants. This is shown by the fact that they have 

 taken possession of so much of the land that they seem to 

 cover it, where plants grow at all. They are also the 

 plants that are most useful to us. When you think of the 

 many ways in which we are dependent on plants, you will 

 see that it is the seed-plants that supply these needs. 



You should know the two groups of seed-plants. You 

 know plants that belong to both of these groups. The pines, 

 hemlocks, cedars, etc., belong to one group. You have 



FIG. 102. Club-mosses. 



