THE FERN BULLETIN 



Vol. XIV. JULY, 1906. No 3 



THE FERN-FLORA OF ONTARIO. 



By A. B. Klugh. 



The Province of Ontario lies between the 42 and 52 

 of N. Latitude, and has an area of 220,000 square miles. 

 The altitude varies from 165 feet at the Quebec boundary 

 on the St. Lawrence to 1706 feet at Dundalk, Grey 

 County, the average altitude being about 950 feet. The 

 mean yearly temperature at Stoney Creek, Wentworth 

 County, is 49.1 °F. ; at Chatham, Kent County, 47°; 

 at London, Middlesex County, 45. 8° ; at Toronto, York 

 County, 44.2 ; at Kingston, Frontenac County, 43.8 ; at 

 Guelph, Wellington County, 43.7 ; at Owen Sound, Grey 

 County, 42.8 ; at Gravenhurst, Muskoka District, 41. 5 ; 

 Ottawa, Carleton County, 41. i°; at North Bay, Nipes- 

 sing District, 39.8 ; at Rat Portage, Rainy River District, 

 36.2 ; at Port Arthur, Thunder Bay District. 34.9 ; at 

 White River, Algoma District, 32.6 ; and at Moose Fac- 

 tory, Nipessing District, 31.1 . 



While temperature has an influence over the distribu- 

 tion of the boreal species, the principal factor in deter- 

 mining the distribution of our Pteridophytes appears to 

 be the outcropping of the different rock formations. In 

 a broad way we may say that in the counties which border 

 on Lake Erie and in the adjacent counties of Middlesex 

 and Oxford, there are few or no outcrops of rock, and 

 consequently an almost total absence of rock species. 

 North of a line drawn from the southern border of Mus- 

 koka to Kingston the outcrops are Laurentian, with the 

 exception of the counties of Russel, Prescott, Dundas, 

 Stormont, and Glengarry, in which limestone appears. 



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