74 THE AQUA TIC GA RDEN. 



flowers of some even of the commonest species, it 

 would be difficult to find an equal number of foreign 

 plants that would excel them in this respect. It 

 should be remembered, however, that the main thing 

 in the selection of aquatic plants is to have such 

 species as will most effectively oxygenate the water. 

 And it is always best to have the vegetable element 

 slightly in excess of the animal, inasmuch as it can be 

 more effectually managed, either by elimination, or 

 by moderating the light which stimulates its growth. 

 The common American weed (Anacharis alsinastum) 

 has never yet been known to flower or seed in this 

 country. It is propagated solely by budding, and we 

 have already said that fish, and especially goldfish 

 and carp, are very fond of nibbling the young and 

 tender shoots. A little of this plant may therefore 

 always be advantageously introduced into a tank of 

 moderate capacity. It must be seen, however, that 

 its tendency to rank growth does not interfere with 

 other and more ornamental plants. 



Another species which has long been utilised in 

 this country by druggists, to oxygenate the water in 

 which medical leeches are kept, is the Vallisneria 

 spiralis. It is a native of the south of Europe, but 

 has been pretty extensively distributed in England. 

 This plant is undoubtedly one of the best and most 

 copious yielders of oxygen of all common fresh-water 

 species, and therefore is of great service in small 

 tanks. Its grass-like leaves show the circulation of 



