146 CYSTOPUS, OR WHITE RUST. 



is smaller. In the SaprolegJiicce the fertilising tubes do not open, 

 and no protoplasm can be observed to pass over from the antheri- 

 dium to the oospheres. Or in some forms no antheridia are 

 present at all, and the parthenogenetic spores are nevertheless 

 capable of germinating. Now, if the Fodosphcera^ already men- 

 tioned, be compared with Ferojwspora, the antheridia will be 

 found to correspond in both cases, and the carpogonium to be 

 homologous with the oogonium of Feronosp07'a. It is remarkable 

 that the antheridium only applies itself closely to the carpogo- 

 nium and does not pierce it, and there is apparently no passage of 

 substance from one to the other — i.e.^ there is no sexual process, 

 though the sexual organs are present. Numerous investigations 

 lead us to conclude that while the sexual organs are present but 

 functionless in these lower Asco7?iycefes, they disappear entirely in 

 the higher forms. 



De Bary concludes that we may regard the FeronosporcB as 

 phylogenetically important in two senses : — i. — Their general 

 biology strongly suggests that they are derived from algal ances- 

 tors, possibly not very unlike Vaiicheria and its allies. 2. — That 

 they are the progenitors of a few chief series of true Fungi — on 

 the one hand, the main series of Asconiycetes and allies ; on the 

 other, the Saprolegniece. and forms derived from and allied to them. 



The Zygomycetes are regarded as branching off from the Fero- 

 nosp07'C(2. Fyf/iinm seems closely allied to the ChytridecE (a group 

 of fungi previously described as being parasitic on the 

 SaprolegniecB)^ and the Chytridece seem allied to the lower Ustilagi- 

 nece by means of the group Frotomyces. According to this 

 view, the resting spores of Ustilagmece. would be the homologues 

 of oogonia which become developed apogamously. 



The Tremelliiii^ a group of well-known gelatinous fungi, 

 belong to the Basidiomycetes, but possess basidiospores, so sugges- 

 tive of the teleutospores of the UredinecE, that De Bary does not 

 hesitate to place them as derived from those Uredinece which 

 possess no aecidia ; whilst those Uredines which form secidia 

 resemble the Asconiycetes in so many points of structure and deve- 

 lopment that we may regard them as closely allied. The Tremel- 

 lini would then lead us to the Hymettomycetes and G aster my cetes^ 

 which form the bulk of the Basidiomycetes. 



