74 EFFECTS OF CLIMATE. 



the sea, is a beautiful and verdant garden, which is 

 entirely surrounded by snows that never melt. This 

 spot is covered with Alpine plants ; and so luxuriant 

 is the growth of the vegetation, that at certain sea- 

 sons of the year the Swiss peasants drive their cattle 

 over the great glacier of Mer de Glace for the sake 

 of the delightful pasture the valley affords. 



In our own country, where so great a variety of 

 climate is witnessed, it is probable that a greater 

 variety of plants can be enumerated than in any other. 

 Our gardens and conservatories are indebted for many 

 of their finest ornaments to the far-off fields and woods 

 of California, Mexico, and the territories west of the 

 Rocky Mountains, countries which combine within 

 their range a climate varying almost from frigid to 

 tropical, and exhibiting at the same season a corre- 

 sponding difference in their floral productions. In 

 the northern and western States, while the cold earth 

 still lies locked in winter's last embraces, the woods 

 of the south are teeming with life, the fields are 

 clothed with the verdure of spring, and the air is 

 scented with the perfume of flowers. But in the 

 regions of tropical Mexico, and the everglades of 

 Florida, vegetation becomes so entirely changed in 

 its character, as to maintain a more uniform appear- 

 ance at all seasons of the year. 



Most plants, whose roots are perennial, have a 

 period of rest, during which they cease to grow ; in 

 the north, this is usually indicated by the falling of 

 the leaves, and the plant assuming the appearance 

 of being dead; in the tropics it is marked by the 



