42 



AQUATIC PLANTS 



of those plants forming a useful adjunct to the breeding of tropical fishes. 

 It multiplies from short runners. Of a pleasing shade of light green, 

 it makes a contrasting group among other plants in a large aquarium, 

 but it shows to best advantage in a small aquarium by itself. It grows 

 from 3 to 8 inches and is native to ponds in the Middle Atlantic and 

 Southern States. Not often obtainable commercially. 



Fig. 25. Potamogeton densus (Half size) 



Fig. 26. Nitella gracilis 

 (Two-thirds size) 



POTAMOGETON 



In strong contrast to the foregoing dainty plants is Potamogeton 

 densus, or pondweed. As will be seen from illustration, 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 



