WATER-PLANTS. 



69 



above the surface. Water animals of many different kinds 

 are fond of making the tangled masses of the Milfoil their 

 head-qnarters. In the aquarium it looks and grows well, and 

 gives off oxygen freely. The greenish flowers grow in whorls, 

 forming a leafless spike about Sin. or 4in. long; its leaves 

 also grow in whorls of four, and are finely divided into 

 hair-like segments. Most appropriately is it named the 



Fig. 50. Vehnal Water Starwort (Callitriche verna). 



Milfoil (the myriad-leaved). It flowers in July and August. 

 A portion (not a bunch) of this plant may be tied to a 

 stone and sunk in the aquarium : it will quickly take root 

 and grow. 



The Vernal Water Starwort (Callitriche verna) (Fig. 50) grows 

 in both slowly-running and stagnant water. The leaves grow 

 in pairs, and are naiTower when found in a stream than Ln a 



