A WORLD IN THE WATER 91 



these which are responsible for the reproduc- 

 tive organs. In the case of the plant under 

 notice the female, or egg cells, are present in 

 close proximity to the male processes. The 

 latter are in the form of rounded bodies of a 

 bright orange colour, sufficiently large to be 

 plainly seen with the naked eye. At the time 

 of maturity these globes open and allow the 

 fertilising element, in the form of spermatozoids, 

 each producing two long hairs, to escape, and 

 these enter the egg cell and in this way com- 

 plete the process. Soon after the egg cells 

 become detached and, sinking to the muddy 

 bottom, lie in a dormant condition for the 

 winter. With the coming of the spring a tube 

 is pushed out from the cell, and this ultimately 

 bears the adult plant. A singular feature of 

 some of the species of Chara is that the plants 

 have the habit of incrusting their delicate stems 

 with lime during the summer months. This 

 gives a curiously brittle nature to the growth. 

 In the autumn, when the plants decay, the 

 accumulation of lime is, of course, left behind, 

 and this deposit may gradually raise the level 

 of the bottom of the pond. There are, per- 

 haps, about half a dozen species of Chara in 



