II. 



OBSERVATIONS ON THE VEGETATION OF THE NORTHERN 

 SHORES OF LAKE SUPERIOR. 



The vegetation of the Northern shores of Lake Superior agrees so 

 closely with that of the higher tracts of the Jura, which encloses the 

 lower and middle zone of the subalpine region, that on glancing at 

 the enumeration below, one is astonished to find so great a number 

 of species entirely identical. Making full allowance for the influ- 

 ence of the lake, and leaving out of consideration a small number 

 of species peculiar to North America, there remains about Lake 

 Superior a subalpine flora which is almost identical with that 

 of Europe, with which it is here compared. Although this fact 

 is very striking, it is nevertheless in accordance with the general 

 laws of botanical geography, and is another proof that the vegeta- 

 tion of the two continents becomes more and more homogeneous the 

 more we advance northwards. 



I have divided the catalogue of the phaenogamous plants collect- 

 ed about Lake Superior into four hsts : The first containing such 

 plants as are really subalpine in their character, or correspond to 

 those of the forests of the lower Alps ; * the second containing the 

 plants of the lake proper, or the aquatic plants ; | the third comprising 

 the plants purely American, | and the fourth the cosmopolitan plants, 

 or those which extend beyond the subalpine region. In the different 



* Only sucli plants are introduced in the first list as have true representatives in 

 Central Europe. 



t Lacustrine Flora; and Fauna; present so many peculiarities that it has been thought 

 best to separate the plants of the lake, which are aquatic, from those of the main land 

 enumerated in the first list. 



X Besides the plants which have true analogues in Europe, there are some about 

 Lake Superior which are truly American types ; these constitute the third list. 

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