CRYPTOGAMS 



179 



(Fig. 297). The egg cells are produced in od'gonia 

 (Fig. 295), found in cavities or conceptacles (Fig. 294), 

 which make their appearance at cer- 

 tain seasons in special portions of the 

 branching thallus (Fig. 293). The 

 antherozoids originate in antheridia 



293. A Branch of Rock- 

 weed : /, a fertile 

 portion. 



THURET. 



294. Section of a conceptacle. THURET. 



(Fig. 296), enlarged cells produced 

 on branching filaments. The anther- 



idial filaments grow from the walls of conceptacles, either 

 with the oogonia, or in other conceptacles upon separate 

 plants, according to the species of 

 Rockweed considered. At maturity 

 both egg cells and antherozoids escape 

 from the concepta- 

 cles and float about. 

 The antherozoids 

 swarm about the 

 naked egg cell ener- 

 getically (Fig. 297), 

 and one of them 



^fi^W^lliFN ^ na ^y penetrates and 

 fuses with it. At 

 An oogouium. once a wall begins 



THURET. tQ form about t ] ie f er tili ze d egg, or 



oospore, which now settles to the bottom, and upon ger- 

 mination gives rise to a new plant. 



296. 



295. 



An autheridial 

 branch ; a, au- 

 theridia. 



THURET. 



