LIVERWORTS 127 



Fertilisation. As in the moss tribe, so with the 

 liverworts, the fruit is developed from the fruit- 

 bearing organ ; but, in order that this may be 

 brought about, fertilisation must first take place, 

 and the steps by which this mysterious process 

 is effected are very similar to those by which a 

 moss plant proceeds at a similar stage of its 

 existence. Several of the fruit-bearing organs 

 (archegonia) may be, and generally are, formed 

 inside a single cup, and though two or three of 

 these may be fertilised, yet one alone will arrive 

 at maturity and produce fruit, the others sooner 

 or later shrivelling up. As the fruit-bearing 

 organ ripens, a tiny passage is formed down its 

 neck, and this leads into a large central cell in 

 the swollen base where a special germ-cell is 

 evolved, from which, when fertilised, the future 

 fruit will spring. As in the case of a moss, so 

 here, the small, round fertilising organ, when 

 ripe, bursts, and sends forth a large number of 

 very minute fertilising bodies (antherozoids) . 

 Each of these consists of a spirally coiled thread, 

 furnished at one end with two fine hairs or 

 cilia, which are sometimes longer than the fer- 

 tilising body itself. By means of these hairs, 

 which vibrate very rapidly, the fertilising body 

 is able to move about in water, and may thus 

 sooner or later find its way to the head of one 

 of the fruit-bearing organs, where, after passing 

 down the tiny passage in the neck, it will fertilise 



