TROPICAL AQUARIUM FLSHPJS 



179 



Fi(.. 127. PoTAMOGETON DEXSUs {Rcduccd onc-halj 

 Fig. 128. Nitell.\ gracilis {Reduced one-third) 



POTAMOGETON 



In strong contrast to the foregoing dainty plants is Potamogcton 

 dcnsiis, or pondweed. As will be seen from figure 127, these leaves are 

 broad and robust. In color they are a bright green. This variety is said 

 to be of European origin but is now common in ponds in the United 

 States. If established in soil in flat pots it flourishes in a well-lighted 

 aquarium. Pieces collected from the wild may be introduced by fasten- 

 ing into the sand. They present a very attractive appearance and will last 

 for quite a time, but should only be regarded as temporary and when the 

 leaves begin to turn yellow should be removed. There are many widely 

 distributed species of Potamogeton, all looking very attractive in a state 

 of Nature, especially P. crisp us with curly leaves. They look very tempt- 

 ing, but none seem to survive in the aquarium except P. detisus and that 

 only when established just to its liking. 



