348 



Introduction to Botany. 



Fig. 190. 



Trees at different elevations on a mountain side. Tiie largest trees occur near the 

 base of the mountain. The darlc zone near the summit of the middle range 

 is a belt of trees, the upper border of which is the timber line, no trees growing 

 beyond this. Above the timber belt is Long's Peak with its perpetual snow. 



