100 FLOWERLESS PLANTS 



duced, whilst in others are present the egg 

 cells. In most cases the sexes are produced on 

 different plants, though this is not invariably the 

 case in all the species of Fuci. At a particular 

 stage in the development of the male cells the 

 spermatozoids escape, and at the same time 

 the female elements {oospheres) are extruded 

 from their hollow. The spermatozoids make 

 their way to the oospheres and bring about 

 fertilisation. Soon after the new plant 

 is bom. Like many other seaweeds, the 

 Bladder Wrack is frequently increased by 

 means of fragments which have become de- 

 tached from the main plant. Many of the odd 

 portions which strew the beach after rough 

 weather will eventually become attached to 

 some rock by a sucker-like disc. 



The other prominent family of the brown 

 seaweeds to which attention should be called 

 is that which is typified by the genus Lami- 

 naria. One species is particularly common, 

 and has been called Laminaria digitata from the 

 fact that the great leaf is divided into segments 

 like so many fingers. The plant has a very 

 large stem, terminating at the bottom in a 

 thick cluster of roots, which hold with the 



