PRIMARY GROUPS OF FUNGI 233 



to our knowledge of the fungi, and the numerous illustra- 

 tions and references to literature far exceed those of any 

 previous work on the subject. 



The classification of fungi presented by Brefeld, the 

 outcome of many years of careful study, as evidenced by 

 his published work, was presented as indicating the true 

 sequence and affinities of the respective groups of fungi. 

 In this particular we now know that he has to some extent 

 failed. But, viewed impartially, it must be admitted that 

 the leading idea running through Brefeld's work, and his 

 main arguments, are based on morphological evidence, and 

 the results of cultures. There is no internal evidence to 

 show that Brefeld ever attempted that line of investigation 

 which alone can enable a person to pronounce with cer- 

 tainty the absence or presence of sexual reproduction in a 

 given group. Brefeld's contention that sexuality, in a 

 potential form, is entirely confined to the Phycomycetes 

 suggests a preconceived view, which, without further 

 evidence, was adhered to. 



A careful examination of Brefeld's latest arrangement of 

 the origin and sequence of the larger groups, here repro- 

 duced, will, I think, support this view. 



The Phycomycetes, or lower, algal-like fungi, are divided 

 into two main groups, the Zygomycetes, whose sexual 

 reproduction results in zygospores. In the Oomycetes the 

 result of sexual reproduction is an oospore. Zygospores 

 and oospores do not play any part in the further evolution 

 of fungi, all later groups being derived from the asexual 

 forms of reproduction present in the Phycomycetes, which 

 are respectively sporangia and conidia, and rests entirely 

 on morphological resemblances. 



It will be further observed that the Oomycetes play no 



