170 



A TEXT-BOOK OF BOTANY 



it, one of them fuses with the egg, and an oospore is 

 formed. It is evident that fertilization can take place 

 only in the presence of moisture. 



A B 



FIG. 165. Marchantia: A, thallus bearing archegonial 

 branches of various ages; B, section through portion of 

 archegonial disk, showing pendant archegonia. After 

 KNY. 



FIG. 166. Marchan- 

 tia: archegonium, 

 containing an egg; 

 sperms seen at the 

 mouth of the neck. 

 After KNY. 



95. The spore-case. 



it begins to germinate; 



B 



FIG. 167. Marchantia: A, spo- 

 rophyte formed within the 

 enlarged archegonium, show- 

 ing the spore-bearing (a) and 

 sterile (6) regions; B, spore- 

 case discharging spores, the 

 sterile region of the sporo- 

 phyte having developed into 

 a stalk. After KNY. 



As soon as the oospore is formed 

 but instead of forming a new Mar- 

 chantia thallus, it produces a very 

 different structure. The oospore 

 germinates just where it was formed, 

 that is, in the bulbous base of the 

 archegonium; and there the new 

 structure grows. When it is fully 

 developed it is seen to consist of a 

 terminal spore-case full of spores, 

 and a sterile base (Fig. 167, A). 

 While growing, this spore-case be- 

 comes anchored in the Marchantia 

 body (that is, in the archegonium- 

 bearing disk) by the sterile base, 



