70 



PRESH-WATEE AQUAEIA. 



pond. It is a very pretty plant, its leaves forming a mass 

 of emerald- green stars on the surface of tte water ; hence its 

 common name. It is entirely submerged, with the exception 

 of the little green flowers which rise above the water in June 

 and July. If this plant is examined, it will be readily seen that 

 it takes its generic name (CallUriche) from its beautiful hair- 

 like roots, some of which slightly enter the soil at the bottom 



of the water; so slightly, 

 indeed, that a small plant, 

 with a little care, may be 

 easily puUed up without the 

 breakage of any of the slender 

 stems. The Vernal Starwort 

 is a great favourite with both 

 female newts and freshwater 

 shrimps {Gammarus fluviatilis), 

 for the former wrap their eggs 

 carefully in the narrow leaves, 

 while the latter find lurking- 

 places in its tangles. There 

 are various opinions concern- 

 ing the suitability of this 

 plant for the aquarium. Some 

 keepers of aquaria declare that 

 it is useless, as it dies so 

 quickly ; while others assert 

 that it is a ready grower, and 

 consequently a good producer 

 of oxygen. There is truth in 

 both these statements, for 

 if it is tied in a bunch to a 

 stone (as it so often is) and sunk in the water of a tank, the 

 lower part of it will soon die, its leaves turning a sickly-looking 

 yellow; but if, on the 6ther hand. Sin. or 4in. of the top of each 

 healthy spray is broken off, and simply floated in the water, it 

 will quickly put forth some hair-like roots, and grow. Under 

 these circumstances it will supply a fair quantity of oxygen, 

 and by its utility and beauty will earn a place in the aquarivun. 



Fig. 51. Autumnal Water Starwort 

 (Callitriche autumnalis). 



