176 



LAKE SUPERIOR. 



LAKE SUPERIOR. 



Populus balsamifera MX. 

 " tremuloides MX. 

 Sparganium natans L. 

 Potamogeton natans L. 



lucens L. 

 pnelongus Wulf. 

 heterophyllus Schreb. 

 pectinatus L. 

 pauciflorus Pursh. 



Triglochin elatum Null. 



Alisma Plantago L. 

 Sagittaria variabilis Engl. 

 Echinodorus subulatus Engl. 



Udora Canadensis Nutt. 

 Vallisneria spiralzis L. 

 Iris versicolor L. 



Juncus effusus L. 

 " acuminatus MX. 

 " paradoxus E. Meyer. 

 " nodosus L. 

 " balticus Willd. 



Eleocharis obttisa Scliultz. 

 " palustris R. Br. 

 " tenuis Schult. 

 " acicularis R. Br. 



Scirpus lacustris L. 



Carex stipata Miihl. 

 " scoparia Schk. 

 " festucacea Schk. 

 " vulgaris 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. 



Jura. 



Potamogeton natans L. 



lucens. L 

 perfoliatus L. 



Quiet 

 waters, 



lakes 

 and riv- 

 ers of 

 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. 

 and Baltic. 



Northern Sea 



Eleocharis palustris R. Br. Marshes. 



Margin 



acicularis R. Br. 

 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- 



