288 



I'AttT III. THE CLASSIFICATION OF PLANTS. 



fuse to form the cell which surrouuds 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 tennis). 



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



in Phycomyces, 

 branched hyphse 

 are developed, 

 after conjugation, 

 from the gatneto- 

 phores, and form 

 an incomplete 

 covering to the 

 zygospore ; and 

 in Mortierella the 

 adjacent vegeta- 

 tive hypbse are 

 stimulated to 

 growth and form 

 a dense hyphal 

 investment to the 

 zygospore. 



In many cases 

 the zygospore, on 

 germinatio n, 

 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 



FIG. 200.-Mucor Mucedo. A Diagram of sexual process ; two a n d 8 a m e * ' 

 pametophores in contact; at the end of each gametophore a cell, phores. In other 

 tVie gainetangium, 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- - ' e to a 

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

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

 sporangium (after Brefeld). ing sexual or- 



