250 FISH CULTUEE 



vertically therefrom, about an incH below the 

 surface. The greater duck-weed (Lemna poly- 

 rhiza), the lesser duck-weed (Lemna minor) 

 and the thick duck- weed, (Lemna gibba) are 

 the most attractive, although they have very 

 little value for oxygenating purposes. 



The water-poppy (Limnocharis humboldti) 

 is one of the handsomest of the surface water- 

 plants for small aquaria, as it possesses small 

 heart-shaped leaves, and yellow, poppy-like 

 flowers about an inch in diameter. The water- 

 crow-foot (Ranunculus aquatilis) is also an 

 excellent plant as a contrast to the water- 

 poppy, having beautiful green leaves, and 

 pretty white flowers with many yellow 

 stamens strikingly like strawberry blossoms. 

 Many aquatic plants live principally in 

 only partially submerged or in wet spots. 

 One of the favourites is the forget-me- 

 not, or Myosotis palustris; and a good foil to 

 the forget-me-not is the umbrella grass (Cy- 

 perus alternifolius). As a finishing touch to 

 the rock work there may be planted the 

 Lycopodium coesium or creeping moss. 



