CHAPTER V. 

 LIFE ZONES. 



By 

 C. D. HOWE, Ph.D. 



IN approaching Toronto from the United States 

 either by the way of Buffalo or Detroit, one finds 

 himself, immediately upon crossing the international 

 boundary, in the Carolinian Area of the Upper Aus- 

 tral Zone of Merriam. The northern boundary of 

 this area may be approximately made by drawing a 

 line from the mouth of the St. Clair River through 

 London to Hamilton, and thence along the lake shore 

 to Toronto. Both the mean annual temperature and 

 the average temperature of the four growing months 

 are slightly higher than the average for the southern 

 portion of the province. The rainfall is somewhat 

 greater and the snowfall is considerably less than the 

 average for the province. 



The milder climate of the southwestern portion 

 of Ontario has resulted in the projection of the flora 

 of the lowland portions of the Southern States into 

 Canada, as is disclosed by the presence of such trees 

 as : the tulip-tree (Liriodendron tulipifera) ; chest- 

 nut (Castanea dentata) ; black walnut (Juglans 

 nigra) ; sour gum (Nyssa sylvatica) ; mockernut 



rry (Hicoria alba) ; Kentucky coffee-tree (Gym- 

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