186 TEXT-BOOK OF FUNGI 



implied by correspondence of sexual organs, the Mucorineae 

 have descended from the algae known as Zygnemae. When 

 we turn to the asexual form of reproduction in the Mucori- 

 neae, the gradual evolution of this generation, so observable 

 in the Oomycetes, is absent. Zoospores are unknown, the 

 conidiophores from the first are as highly organised as in 

 the highest of the Oomycetes, and the reproductive bodies 

 or spores contained in highly specialised sporangia seem 

 to be derived directly from the simpler forms met with in 

 the Oosporeae. In other words, the asexual or conidial 

 generation in the Zygomycetes commenced where the 

 same structure in the older Oosporeae left off, and con- 

 tinued evolving in accordance with the requirements of 

 aerial surroundings. There is no starting-point of primitive 

 simplicity in the conidial generation, as would be expected 

 from analogy with the Oosporeae, if the Mucorineae had 

 broken away independently from the Zygnemae. 



Next in order come the Ascomycetes, characterised by 

 having spores considered as the result of a sexual act, pro- 

 duced by free cell-formation within a mother-cell o.r ascus. 

 In many species the sexual organs consist of an anther- 

 idium and oogonium as in the Oomycetes. But in 

 numerous other species we are introduced to an appar- 

 ently totally different type of sexuality. The male or 

 fertilising element consists of minute non-motile bodies ; 

 these adhere to a more or less slender outgrowth of the 

 female or receptive organ, called a trichogyne. Now this 

 type of sexual organs resembles the one characteristic of 

 the Florideae or red seaweeds at the present day, what- 

 ever it may have been in the remote past, when those 

 fungi characterised by the presence of a trichogyne are 

 supposed to have evolved from the Florideae. It so 



