92 THE AQUATIC GARDEN. 



for aquaria. The flower spikes are densely set with 

 small reddish flowers, and are slightly raised above 

 the surface of the water. The leaves are brownish- 

 Fig. 42. 



Water Star- wort (Callitriche verna) ; a, b, flowers. 



green, and very thin and prettily veined. These leaves 

 are usually submerged, but few of them persistently 

 floating on the top. 



Besides these aquatic plants, useful for aerating 



