THE ALGAE 



159 



extensive tissue is developed by means of the gonimoblast filaments before 

 the carpospores are produced. This tissue, since it is derived from the 

 fertilized carpogonium, is diploid and is termed the carposporophyte. Its 



Fig. 146. — Chondrus crispus. Development of 

 tetraspores in tissues at margin of thallus. 



existence is terminated by the carpospores, which in turn give rise to diploid 

 tetrasporophytes. The reduction division occurs in the formation of the 

 tetraspores which on germination initiate a gametophyte. Thus in this 

 Alga, as in many other members of the Rhodophyceae, there is an alternation 

 of not two but three generations. 



The life-cycle of Chondrus may, therefore, be represented by the diagram 



(Fig- 147)- 



Tetrasporophyte 



Carpospores 



CarposporoptiYte 



Tetraspores 



Spermatium 



Female 

 Nucleus 



Anthendtum Carpogonium 



Gametophyte Riant 

 Fig, 147. — Life-cycle of Chondrus. 



