Aquarium Plants 55 



form new plants. The easiest and quickest 

 way to propagate the plant is to take branches 

 and plant them in sand or in a mixture of 

 sand and soil. The blossoms of the Potamo- 

 geton are not ornamental and may be re- 

 moved before they develop. All Potamoge- 

 tons are good oxygenators. 



Potamogeton perfoliatus. This pondweed 

 has much shorter leaves than Potamogeton 

 crispus. They are generally ovate and 

 slightly serrated near the point. The stem 

 grows through the base of the leaves, which 

 form a rather dense growth and are all sub- 

 merged. It grows very well even in small 

 aquariums and keeps remarkably free from 

 alga?. 



Dense Pondweed {Potamogeton deiisus) re- 

 mains bright green in the aquarium all 

 winter. It has two kinds of leaves. Those 

 growing under water are long and slender, 

 almost ribbon-shaped on the base; but as 

 the plant grows, reaching the surface of the 

 water, it forms swimming leaves, which are 



