Classification, 71 



Phycomycetes. 



The amount of work yet to be done in the present 

 group, even to place it on a level with any other 

 group of fungi, can only be realized by studying the 

 systematic work by Saccardo,^ where all the described 

 forms are brought together. It is safe to say that 

 the greater proportion of so-called genera and species 

 are only temporary^ owing to the fact that our 

 amount of knowledge is so scanty, embracing in but 

 comparatively few instances a complete life-history, 

 hence in almost every genus comprising half-a-dozen 

 species or even less, it is usual to find some species 

 founded on a knowledge of the gonidial phase alone 

 while others are characterized by peculiarities pre- 

 sented by the sexual organs, the gonidial condition 

 being unknown. As a rule, throughout the group 

 the gonidial is far more constant than the sexual 

 mode of reproduction, and carefully conducted inves- 

 tigations teud to show that in some instances either 

 one or the other has been entirely suppressed, most 

 frequently the latter, as in Flnjtoptliora infestans. It 

 is also proved that in many other cases where 

 both antheridia and oogonia are present, fertilization 

 does not take place, that is, no protoplasm passes 

 from the germ-tubes of the antheridia into the 

 oospheres. In other instances the antheridia are not 

 developed, consequently the oospores produced by 

 the oogonia are asexual in origin; both these con- 

 ditions are met with in the Saprolegniese. A typical 

 zygospore originates as follows : the two lateral 



5 SjU. Fung., vol. vii. Part I. 



