216 CEOSSING THE ANDES. 



but recall the diiFerent zones of vegetation through which 

 we had passed. Xowhere in the world does Nature crowd 

 together such a diversity of climate, as there directly 

 under the line of the equator. Just above where we stood 

 reigned the snows of an eternal winter, below, the con- 

 stant heat of the fervid tropics, while the vales between 

 enjoyed the freshness of perennial spring. In three days 

 we had passed from the rank, stimulated grow^th of the 

 ticrra caliente, to the stunted vegetation of a few hardy 

 Alpine plants, struggling for an existence amid the melt- 

 ing snows of Chimborazo. The decrease of vegetation as 

 we ascend mountain-slopes, as well as its inferior organi- 

 zation, is the result not only of a diminution of heat, but 

 also of the existence of less carbonic acid in high regions 

 of the atmosphere. Lichens, " children of the rocks," are 

 starved as well as frozen. It is curious to observe the 

 wide range of conditions to which vegetable organiza- 

 tions are adapted. With our plants gathered amid the 

 snows of the Andes, are some found growing under the 

 peculiar conditions afibrded by the crater of Pichincba, 

 and still others taken from the Stygian waters of the hot 

 springs of Valencia, Specific characteristics adapt each 

 variety to these widely-diverging conditions of life. Find- 

 ing species so admirably fitted to circumambient condi- 

 tions, the question is naturally suggested, how far these 

 adaptations are referable to individual adjustment, ren- 

 dered possible by the plastic nature of primal forms. 

 This is one of the most interesting questions awaiting the 

 solution of naturalists. 



The bright color of the floAvers of these high altitudes 

 is refreshingly attractive to the eye of the traveller ; ren- 

 dered doubly so by the gray, sear, sombre appearance of 

 the scene which they deck like sparkling jewels. A beau- 

 tiful deep blue and bright yellow are the favorite colors 

 of these Alpine plants. The cause of the peculiar coloring 



