138 



MANUAL OF BOTANY 



mucilaginous, and the neck of tlie archegonium opens by the 

 separation of its cells. 



Fertilisation is effected by the entry of an antherozoid 

 into the neck of the archegonium and its ultimate fusion with 

 the oosphere at its base. The mucilaginous matter ejected from 



Fig. 896. 



Fig. 897. 



Fig. 896. 1-3. Development of the autheridlum of the Pern, 5. Anthero- 



zoids escaping. After Kny. Fig. 897. Development of archegonium in 



the Fern. The figures indicate successive stages. 3 and 6 are transverse 

 sections of the neck in two stages. After Kny. 



the archegonium is said to contain a substance, probably malic 

 acid, which has an attraction for the antherozoid, enabling 

 the latter to find its way to the canal of the neck. 



When fertilisation has been effected the oosphere clothes 

 itself with a cell-wall, and becomes the zygote, or oospore. It 



