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 Austral 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 tulipif era) ; chest-nut (Castanea dentata) ; black walnut (Juglans nigra) ; sour gum (Nyssa sylvatica) ; mockernut hickory (Hicoria alba) ; Kentucky coffee-tree (Gym-