INTRODUCTION 5 



this view ; the marked difference in origin of the spores in 

 sporangia and asci respectively being thought inconceiv- 

 able in homologous organs. Later research, however, has 

 shown that Harper's definition of an ascospore, founded 

 on a very limited number of observations, is not of general 

 application. 



Blackman, in addition to the discovery pf sexuality in 

 the aecidium stage of the Uredineae, also announces the 

 presence of a rudimentary trichogyne. This indicates an 

 affinity with the Florideae or red seaweeds, where the 

 trichogyne is still of functional value in fertilisation. A 

 trichogyne is also present in the Ascomycetes, where in 

 some cases, more especially in the members of Thaxter's 

 Laboulbeniaceae, it exercises its function of being the 

 intermediary between the spermatia, or fertilising bodies, 

 and the receptive cell. In other genera, as Poly stigma^ 

 Poronia^ etc., the trichogyne is functionless or rudimentary. 



The occurrence of a trichogyne in such widely separated 

 groups of [fungi is considered to suggest more than one 

 independent break away from the algae, which are by 

 almost universal consent considered as the ancestors of 

 the fungi. 



It is only justice, however, to state that Brefeld's view 

 of the phylogeny of fungi does not agree with the above 

 statement. According to this author the algae and fungi 

 probably sprang in two distinct lines from the Schizo- 

 phyta. The lowest group of fungi is the Phycomycetes= 

 Zygomycetes and Oomycetes. From these are descended 

 the Mesomycetes = Hemiasci and Hemibasidii. From these 

 again are derived the Mycomycetes = Ascomycetes and 

 Basidiomycetes. 



In the Basidiomycetes and the Uredineae the cells 



