48 THE WORLD IN WHICH WE LIVE 



the pink moccasin flower stands up straight and tall 

 between its two long, slender leaves. 



There are the forest societies and the societies of 

 the mountain tops where the trees cannot grow and 

 where only the little Alpine flowers and strange 

 looking mosses grow up to the foot of the melting 

 ice. And there is the great society which we know 

 best, that of the ordinary fields and roadsides. 



Now in whatever society a plant belongs there it 

 will grow best. It may be able to live in another, 

 but it will not thrive. Trees which grow so large 

 and spreading upon the river bank will die if the river 

 is so full that they stand continually in the water, 

 as the plants of the marsh society do. The pretty 

 columbine nodding from a cleft in the rock could 

 not live in the open fields with the bird's-foot violet. 

 Nevertheless it is quite wonderful to see what 

 some plants will do to adapt themselves to hard 

 conditions. 



Those forest trees that grow up straight and tall 

 to reach the sunlight do not die, even if they are some- 

 what crowded. The trees that grow upon the open 

 hillsides have to do battle with the wind ; they cannot 

 grow as tall as does the tree on the level plain. They 

 must grow strong to be able to withstand the wind. 

 The energy which the forest trees use to grow tall 

 they must use to grow strong. 



In a time of very dry weather many plants will 

 move their leaves. The Indian corn will roll up its 

 long leaves to save the moisture in them from being 

 evaporated and the sensitive plant will shut to- 

 gether the small leaflets which compose the large 



