localities in Jutland and found the plant in some places, 

 where the heigth of the water was lower than was normal; 

 it then lay in the surface of the water , was less branchy 

 and much more rich in flowers. 



The plate is drawn by Mrs. Raunkiser after speci- 

 mens from Gudenaa, conserved in alcohol. The analyses are 

 drawn by Mr. Raunkiasr, to whom I am also indebted for 

 corrections of this essay. 



