CHAPTER X 

 PHYLOGENY OF THE FUNGI 



One of the most consistent attempts at representing the phylogeny 

 of the fungi has been made by Dr. 0. Brefeld through his researches 

 which were pubHshed in collected form in " Untersuchungen aus dem 

 Gesammtgebiet der Mykologie. " As these volumes are bulky ones, a 

 student of Brefeld, Dr. F. von Tavel, has given a useful summary of 

 the chief points in his teacher's system in a book published in 1892, 

 entitled " Vergleichende Morphologie der Pilze." The phylogeny of the 

 higher fungi, according to Brefeld, is based on the assumption, that 

 there is an entire absence of sexual organs in all of those groups above 

 the PHYCOMYCETES, but this view has been rendered untenable 

 owing to the discovery of undoubted sexual organs among the ASCOM Y- 

 CETALES and the discovery of nuclear fusions in some of the rusts, 

 suggesting a sexual condition. However this may be, Brefeld and von 

 Tavel hold that the PHYCOMYCETES are algal-like fungi and prob- 

 ably derived from algal ancestors. 



The OOMYCETALES are not linked directly with any of the higher 

 fungi, but the ZYGOMYCETALES through the former with sporangia 

 and conidia have probably given rise to the HEMIASCI and directly 

 through them to the ASCOMYCETALES. The forms of ZYGOMY- 

 CETALES with conidia above are phylogeneticall)'^ connected in the 

 Brefeldian system though the HEMIBASIDII with the BASIDIO- 

 MYCETALES. This in brief is an outline of the phylogenetic views 

 of Brefeld, as expressed in a useful ground plan of the natural system 

 of hyphal fungi by von Tavel. 



The question is asked naturally, whether the origin of the fungi has 

 been monophyletic, that is from a single ancestral form, or polyphyletic, 

 from a number of distinct ancestors? This question can be answered 

 only after an examination of the evidence. There are two orders of the 

 PHYCOMYCETES, or algal fungi, namely, ZYGOMYCETALES and 

 OOMYCETALES. As to the origin of these forms, the monophyletic 

 view would have us derive the ZYGOMYCETALES from the OOMY- 



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