number of others which in Canada are confined to Pt. 

 Pelee or Pt. Pelee Island, spots only a few miles distant 

 from the islands of Ottawa and Erie counties, Ohio. 

 The Sandusky district contains 67 native plants not 

 known to grow anywhere in Michigan and many 

 others which in Michigan are confined to the south- 

 western part where the climate is tempered by Lake 

 Michigan. But what seems quite as remarkable is the 

 fact that the Sandusky district contains 305 native 

 plants not known to grow within fifty miles of Buffalo, 

 while the Buffalo district has about 244 native species 

 and varieties not given in the Sandusky list. But even 

 this great difference between two regions bordering on 

 Lake Erie is largely due to climate, for the summer at 

 Buffalo is not only cooler but lasts less than three- 

 fourths as long as at Sandusky. Since the prevailing 

 winds have traversed Lake Erie for nearly its whole 

 length before reaching Buffalo the mean temperature in 

 summer there is about 3° lower than at Sandusky. In 

 the spring the difference is even greater than in summer, 

 being about 5^4° lower in April and May. This is due 

 to the fact that when the ice breaks up it is blown to 

 the east end of the lake and remains so crowded there 

 as to prevent navigation three weeks or more after 

 Sandusky Bay has been clear. The average date of the 

 last killing frost in spring in Sandusky, is April 14; at 

 Buffalo, May 20, that is 36 days later. Moreover, San- 

 dusky is protected by its position from cold north-west 

 winds in autumn, while Buffalo is not, so that the first 

 killing frost at Sandusky does not come on an average 

 until October 23, but at Buffalo October 5, that is 

 18 days earlier. 



Like an east and west mountain range, Lake Erie 

 protects the plants on its south side from cold north 

 winds while they get the full force of winds from the 

 south, but with the vegetation on the north side it is 

 the reverse. Moreover, the heat given out by the 



