CR YPTOGAMS 



179 



(Fig. 297). The Qgg cells are produced in oogonia 

 (Fig. 295), found in cavities or concejjtaclea (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 Qgg 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 

 finally penetrates and 

 fuses with it. At 

 295. Au oogonium. — once a wall begins 



to form about the fertilized Qgg-i or 

 oospore^ which now settles to the bottom, and u]3on ger- 

 mination gives rise to a new plant. 



296. 



An antlieridial 

 brancli ; a, an- 

 theridia. 



— Thuret, 



