288 



TART III. THE CLASSIFICATION OF PLANTS. 



fuse to form the cell which surrounds itself with a coat of two layers and 

 becomes a zygospore (Fig. 200). Azygospores are frequently produced, ex- 

 clusively in some cases (Mucor neglectus and tenuis). 



In some forms the effect of conjugation extends to the adjacent hyphaa ; thus, 



in Phycomyces, 

 branched hyphas 

 are developed, 

 after conjugation, 

 from the gameto- 

 phores, and form 

 an incomplete 

 covering to the 

 zygospore ; and 

 in Mortierella the 

 adjacent vegeta- 

 tive hypbffi are 

 stimulated to 

 growth and form 

 a dense hyphal 

 investment to the 

 zygospore. 



In many cases 

 the zygospore, on 

 germination, 

 gives rise to a 

 small branched 

 or unbranched 

 mycelium, which 

 bears a single 

 simple sporo- 

 phore resembling 

 the gonidiophore 

 of the plant to 

 which it belongs. 

 The spores de- 

 rived from this 

 sporophore give 

 rise, on germina- 

 tion, to the large 

 mycelium bearing 

 gonidiophores 



and gameto- 

 PIG. 2CO. Mucor Mucedo. A Diagram of sexual process ; two 



gametophores in contact ; at the end of each gametophore a cell, P ( 

 the gametangiom, has been cut off by a septum; B commencing cases, however, 

 development of the zygospore from the fused gametangia ; C ripe the zygospore 

 zygospore, still connected with the gametophores ; D free zygo- 

 spore, showing one point of attachment ; E germinating zygo- 

 spore, bearing a small promycelium, the sporophyte, with a single 

 sporangium (after Brefeld). 



gives rise to a 

 mycelium bear- 

 ing sexual or- 



