PRESENT-DAY DISTRIBUTION 



erated. In Europe they were swept almost to the 

 very fringe of the Mediterranean and virtually all 

 destroyed. In Europe to-day, only about three 

 dozen genera of trees are found and even the species 

 are very limited in number. 



We are not concerned with the theories as to what 

 particular astronomical change induced the Ice Age, 

 but it is important to realize that the ice did not 

 descend to equal latitudes all round the Northern 

 Hemisphere. Japan and China escaped glaciation 

 and, though the temperature must have been lowered, 

 the vegetation suffered little harm. Of course there 

 was a migration toward the south and a reverse 

 one at the close of the glacial epoch. The net result 

 is that the existing flora of the Chinese Empire and 

 of central Japan southward, is really a miniature of the 

 whole flora of the Northern Hemisphere in pre-glacial 

 times. In China and in the parts of Japan indicated 

 grow to-day many peculiar types, and all the princi- 

 pal genera of trees known from the other parts of the 

 Northern Hemisphere except Robinia, Laburnum, 

 Platanus, true Cedars (Cedrus), Sequoia and Taxo- 

 dium ; and of the latter two there are such very closely 

 allied trees as Taiwania and Glyptostrobus. Fossils 

 of many types which grow in the Orient to-day occur 

 in Europe, and recent dredgings off the Dutch- 

 English coast have added much to prove that the 



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