176 



LAKE SUPERIOR. 



Lake Superior. 



Populus balsamifera Mx. 

 " tremuloides Mx. 

 Sparganium natans L. 

 Potamogeton natans L. 



" lucens L. 



" prselongus Wulf. 



" heterophyllus Schreb. 



t' pectinatus L. 



" pauciflorus Pursh. 



Triglochin elatum Nutt. ' 



Alisma Plantago L. 

 Sagittaria variabilis Engl. 

 Echinodorus subulatus Engl. 



Udora Canadensis Nutt. 



Vallisnerla spiralzis L. 



Iris versicolor L. 



Juncus effiisus L. 

 " acuminatus Mx. 

 " paradoxus E. Meyer. 

 " nodosus L. 

 " balticus Willd. 



Eleocharis obtnsa Schultz. 

 " palustris R. Br. 

 " tenuis Schult. 

 " acicularis R. Br. 



Scirpus lacustris L. 



Carex stipata Miihl. 

 *' scoparia Schk. 

 " festucacea Schk. 

 " vulgai'is Fries. 

 " stellulata Good. 



Europe. 



latitudes, shows their closer con- 

 nection with the nature of the 

 ground than with the temperature 

 of the country where they grow. 

 Populus nigra L. > 

 " tremula L. _> 

 Sparganium natans L. 

 Potamogeton natans L. 

 " lucens. L 



" perfoliatus L. 



Jura. 



1 Quiet 

 waters, 

 I lakes 

 j and riv- 

 ers of 

 J Europe. 



Triglochin palustre L. This species 



occurs also in N. America. 

 Alisma Plantago L. ") ^^ 



Sagittaria sagittifolia L. y 

 Echinodorus is an aquatic type peculiar 



to the American flora. 

 Udora occidentallis Pursh. Northern 



Germany. 

 Vallisneria spiralis L. Lombardy and 



Tessino. 

 Iris pseudc-acorus L. Margins of 



waters. Everywhere. 

 Juncus effusus L. 

 " acutiflorus Ehrh. 



" balticus Willd. Northern Sea 

 and Baltic. 



Eleocharis palustris R. Br. Marshes. 



" acicularis R. Br. Margin 



of lakes and marshes. 



Scirpus lacustris L. Common in all 

 lakes of Switzerland. 



Many of these species are the same in 

 the two continents ; but there 

 are at the margin of waters of 

 the whole middle and northern 

 Europe, many more Cariees re- 



