474 BOTANY OP LAKE HURON. 



a complete, representation of tlie Flora of the sand-area of the eastern 

 coast of Lake Huron. 



As the whole area explored, owing to geographical position and 

 physical features generally, favoxirs alike a northern, southern, and 

 provincial climate, so we find the vegetation more or less naturally 

 divided into three sections, which it is deemed proper to consider' 

 separately : — - 



1. Boreal Type.— Species found in greater, abundance on Lake Superior and 



northward, and most of which have migrated southward. 



2. Peovincial Type. — -Species more or less generally distributed throughout 



the Province. 



3. Austral Type.— Species more characteristic of more southern latitudes, 



and which have probably migrated from the south. 



Boreal Type. — The species partaking of an undoubted boreal 

 nature are for the most part confined to the Bruce Peninsula, the 

 southern portion of the Georgian Bay, and the so-called Fishing 

 Islands lying a few miles off the Bruce coast of Lake Huron. The 

 southern limit may be set at the mouth of the Bivifere aux Sables 

 (north), south of which, as has been remarked above, the vegetation 

 approaches that of the sandy plains of the A ux Sables further south. 

 Strictly speaking, however, plants of a marked northern range are of 

 frequent occurrence throughoxxt the Province, distributed more espe- 

 cially through our swamps of tamarack and cedar. It is well known 

 that districts whose drainage is impeded by physical or other causes 

 become natural sources and habitats of plants demanding a tempera- 

 ture much below that required by our woodland si^ecies, or those on 

 the southern slopes of our sand and gravel ridges. Botanically con- 

 sidered, these swamps or peat bogs dimly represent outliers or isolated 

 portions of the great Arctic or Scandinavian Flora, and thus with ' 

 historic interest bear testimony, as conclusive as do the Alpino- Arctic 

 types of the White Mountains and the Pyrenees, to the former 

 almost universal extension of the Artie Flora over the temperate 

 zone, and its comparative degree of continuity, as evinced by thfe, 

 occurrence of representative species in regions physically adapted for 

 boreal forms. These depressions of surface occupied by peat bogs, or 

 lakes and ponds with which such localities are often studded, are of 

 frequent recurrence throughout the area indicated by the title of 

 this paper. From the plains of the Aux Sables (south) to the lati- 

 tude of Goderich, the Cedar (Thuya occiden talis) is eminently charac- 



