290 NOTES ON THE FLORA OF HAMILTON. 



exercise on the boundary lines of widely distributed plants. Thes •> 

 great bodies of never-freezing water must give tbe western part of 

 Ontario a climate in many respects approximating to tbat of the sea 

 coast. The influence of the sea on the range of plants in Europe has 

 been thoroughly investigated by Grisebach and others, and many 

 curious relations between the various factors of climate and the 

 different species of plants have been established. On that continent 

 the majority of plants have either a north-western or a north-eastern 

 boundary line — i. e., their northern boundary lines are not coincident 

 with parallels of latitude, but intersect them. For example, the 

 European Chestnut has a north-eastern limit running from the south 

 of England to the Lake of Constance, or from about 52° to about 48° 

 of North latitude. On the other hand, the boundary line of the. 

 European Silver Fir (Pinus picea, L.) crosses this at right angles, 

 running from about 43° in the Pyrenees to about 52° in Poland. 

 Grisebach's inference from this is that the Chestnut requires a long 

 summer, the Silver Fir a hot one. It would be interesting to know 

 "whether the relations between our Balsam Fir and our Chestnut, the 

 corresponding trees on this continent, are the same. In one respect, 

 at any rate, I think they ai'e different. For reasons given above, it 

 would seem that the northern limit of the American Chestnut is fixed 

 by the severity of the winter, and not by the length of the summer. 



With the view of throwing, if possible, a little light on the 

 important question raised in the preceding paragraph, I have inves- 

 tigated the direction in which each of the 71 native plants occurring 

 at Hamilton, but not at Belleville, extends farthest. For ten I can 

 ■ give no direction, but fourteen may be described as northern, one as 

 north-eastern, two as south-eastern, thirty-four as southern, seven as 

 south-western, two as western, and one as north-western. This result 

 would seem to show that the Great Lakes exercise an influence in 

 bringing the boundary lines of plants, which would otherwise run 

 parallel to or at right angles with the Atlantic coast, more into con- 

 formity with the parallels of latitude. I am inclined to think, how- . 

 ever, that, although this is in a certain sense true, it will be found 

 that the curve of the boundary line of many plants is in Ontario 

 most remarka,ble and decided. For example, the Early Frost Grape 

 ( Vitis riparia, Mx.) occurs both at Hamilton and Colling wood, but 

 not at Belleville. The Cranberry {Viburoium Opulus, L.) and the 

 Ninebark (Spircea opulifolia, L.) have been found at London and at 



