32 



iety of luxuriant species. As we ascend 2,000 or 3,000 feet the composi- 

 tion changes and we have come into the deciduous leaved forest, not unsim- 

 ilar in general aspect to that of our middle latitudes. We reach a sandy 

 plateau and find it occupied with pines and saw palmetto as underbrush, 

 just as we see it in the Carolinas. As we ascend to the 8,000 foot level, we 

 enter into the dominion of spruces and firs, and we may find thye open mea- 

 dows with a profusion of flowers. These openings, in Colorado and other 

 parts of the Rockies, are characteristically called parks. Here a depression 

 has filled up with water, forming a lovely mountain lake, with the spruces 

 and firs in spiral shapes surrounding the shores, just as you find them in 

 British Columbia at lower levels. Another 2,000 to 5,000 feet, and the 

 xorest opens as in our northward journey, the trees stand in groups, and the 

 grass and flowers occupy intervening spaces, competing for the ground. 

 As we pass out of this lovely park-like region, we come in sight of the peak 

 and of the skirmish line of the forest ; singly and in small groups the trees 

 try to brave the blast, hugging the ground and each other for protection, 

 tousled and dwarfed as their northern counterparts. Ice-laden with the 

 frozen humidity of these high attitudes for months the branches break. 

 This leads to misshapen form. Finally we have passed die limberiine, 

 where icy blasts and hard frosts occur every month in the year and hence 

 no persistent life can exist; and, if we are quick about descending, we may 

 again rest under the palms at night. 



While, then, certain territory is assigned to the different tribes of tree 

 species, which are adapted to the climatic and soil conditions, struggling to 

 occupy the ground and to wrest it from the lower vegetation, there is by no 

 means an end to the evolutionary struggle, for, as soon as the soil is con- 

 quered, the battle begins between the conquerors themselves. Though not 

 fought with claws and teeth, the struggle is as fierce, as persistent and as 

 disastrous to the one or to the other species as in the animal world, each 

 trying to occupy the ground to the exclusion of the other. The weapons 

 and the warfare are offensive and defensive, but relative endurance of one 

 or more unfavorable conditions, adaptation to surroundings, insure mostly 

 the final victory and secure the survival of the fittest. The characteristics 

 of development from the-seed to old age influence the character of the dis- 

 tribution. 



Prolific and frequent production of light-winged seed, carried by the 

 wind to all open spaces, germinating readily and growing rapidly, gives an 

 advantage to the one species. The heavy nut of the walnut or acorn must 

 wait for squirrels, mice, birds and water to extend its territory. 



The seed of the willow loses its power of germination within a few 

 hours or days ; hence it is confined mainly to the borders of streams, where 

 favorable opportunities for sprouting exist. The acacia and others of the 

 leguminous tribe, like the black locust, preserve their seed alive for many 

 years ; nay, the seed of the former will often lie buried in the ground for 



