246 



HANDBOOK OF NATURE STUDY 



Iceland moss, which you can buy in every drug store, is a 

 lichen, as is also the reindeer moss, about which you have 



probably heard. 



Scholars who have given 

 many years to the study 

 of mosses and lichens have 

 found hundreds of species 

 of each group ; but the 

 principal question with us 

 is the importance of these 

 plants in the economy of 

 nature. 



They are the first plants 

 which appear on bare rocks, 

 where no life could exist 

 before them. 



Soon the lower parts of 

 mosses die, but the dead 

 rootlets and stems furnish 

 a better soil for the green 

 tufts on top. This thin 

 turf holds the rain water 

 for some time, and also 

 catches dust and sand 

 which the winds drop on 

 it. Thus a thin layer of 

 soil is formed, in which 

 larger plants can find a 

 footing, and in which in- 

 sects and worms can bur- 



FIG. 48. 



To the left, three plants of Poly- 

 trichum commune, slightly re- 



row. 



Of great importance for 



duced; to the right, a plant of man Qre tj(e eat mosses , 



Nnhnnniim rtintnifnhiim slurht.lv 



Sphagnum cymbifolium, slightly 

 reduced. 



For hundreds and thou- 



