PRESENT-DAY DISTRIBUTION 



Caucasus region, in eastern North America and in the 

 Orient. What were temperate regions in the north 

 in Tertiary times are even now the frozen North, 

 and the land of this region capable of growing forests 

 is infinitely less than it was then. Deserts, seas, 

 lakes, high plateaux, and mountain ranges influence 

 climates, which strongly affect plant distribution. 

 Birds, animals, air- and water-currents are all agencies 

 in plant dispersal, and so to understand why this tree 

 is here and not yonder involves the study of a num- 

 ber of cognate branches of natural history. Com- 

 plex is the problem, but however little it is studied 

 the marvels of the world we live in become more and 

 more apparent. 



Brief and fragmentary as this sketch is it would 

 be more so did we omit mention of the influence of 

 man. At what period in the world's history man 

 first appeared is much disputed, but certain it is 

 that, as soon as he became a sentient being, hunger 

 caused him to investigate the vegetation and taught 

 him to appreciate what was wholesome as food; pro- 

 viding himself with clothes, shelter, and weapons for 

 protection followed. As he migrated so he carried 

 with him plants that were of service to his needs, 

 and, later, such as were a delight to his higher 

 being. We know so little of the early peregrinations 

 of the human race, or of where it had its cradle, that 



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