Aquarium Plants 43 



During the winter this plant is only partly 

 green. (See Fig. 16, page 35.) 



The leaves surround the stem in whorls 

 and are very finely divided in almost thread- 

 like filaments. It is one of the most com- 

 mon pond plants, found in most parts of the 

 United States, but varying considerably ac- 

 cording to its habitat. In southern waters 

 it grows very much denser and darker, even 

 with a reddish tint, so that it looks almost 

 like a different species. 



Canadian Waterweed (Elodea canadensis) 

 is a rank grower, forming a network of 

 long slender branches with three or more 

 small leaves arranged around the stem in 

 circles. The young branches are of a light 

 bright green. It grows most readily, even 

 from the smallest piece of stem with some 

 leaves thrown in the water, but it is prefer- 

 able to fasten the stems in the bottom gravel. 

 As it is inclined to a very rapid growth, it 

 has to be watched and pruned, to prevent its 

 encroaching upon the sites of other and pos- 



