MOUNTAIN OR ALPINE VEGETATION 485 



which trees can grow, or as it is commonly called in this coun- 

 try the "timber line," is somewhat over twelve thousand feet 

 in the equatorial Andes, and lessens in higher latitudes as one 

 goes either way from the equator, until in the arctic regions it 

 reaches sea level. In the White Mountains, for instance, the 

 timber line only rises to about forty-five hundred feet. The seed 

 plants of alpine regions in all parts of the earth have a peculiar 

 and characteristic appearance. It is easiest to show how such 



FIG. 370. Trees near the timber line on the slope of Pikes Peak 

 After W. M. Davis 



plants differ from those of the same species as they look when 

 growing in ordinary situations by reference to the plants them- 

 selves or to good pictures of them (see Fig. 372). The differences 

 between alpine and non-alpine plants of the same or closely 

 related species have been summed up as follows 1 : " The alpine 

 individuals have shorter stems, smaller leaves, more strongly 

 developed roots, equally large or somewhat larger and usually 

 somewhat more deeply colored flowers, and their whole structure 

 is drought-loving (xerophilous)." 



' By A. F. W. Schimper. 



