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Chapter Thirteen 



Aquarium Plants 



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Whether aquaria are kept for scientific study or for the enjoyment 

 of the beautiful, aquatic plants will always be found a useful, if not 

 indispensable, adjunct. The fact that plants give off oxygen under 

 the influence of light has been mentioned at several other places in 

 this volume, but the principle is so important that it would be difficult 

 to over-emphasize it. Aquaria containing good plant growth may be 

 tightly covered and if placed in a good light they will support a fair 

 number of fishes, the life-giving oxygen in such an experiment being 

 supplied almost exclusively by the plants. 



That the roots of healthy aquatic plants absorb the products of 

 decomposition in the bottom of the aquarium is an established fact. 

 When an aquarium has been established for some time, the sand has 

 become a little dirty and the plants have spread so that the roots of 

 some are against the glass, a close observation will show a condition 

 similar to that pictured in Figure 158. The sand near the roots is dis- 

 tinctly whiter than that beyond their reach. 



No arguments need be put forward 

 to establish the aesthetic value of plant 

 life in the household aquarium or the 

 pool in summer. Without them no one 

 could attempt to reproduce the effects 

 of Nature. So well understood is the 

 value of aquatic plants that aquarists 

 are constantly on the lookout for any- 

 thing new which might enhance the 

 beautiful results already achieved. 

 Occasionally something of real merit is 

 Pjq i5g found. We are pleased to be able to 



Absorption by Plant Roots 1'^* several of these newer species here, 



