138 TKANSACTIOXS AND PROCEEDINGS OF THE [Sess. LXiir. 



Ascomycetes, and that the ascus-geueration is a parasitic 

 sporophyte. This view is supported by Lagerheim's 

 observations on Dipodascus (6), Eidam's on Eremascus, 

 Harper's on Sphaerothcca, and Thaxter's on the Labonlbeniei^ 

 (5), as well as by a number of other more dubious instances. 

 The eases of Dipodascus, one of the Hemiascinere, and of 

 Eremascus, one of the Protascinefe, both point in the same 

 direction, namely, that already in the archetype of the 

 Ascomycetes, the product of fertilisation was a cell (spore)^ 

 which germinated fructiticatively by giving rise to a single 

 sporangium (ascus).^ The stages by which a complete 

 generation, with sexual organs and sporangia, might be 

 reduced to a single sporangium, are denoted in the method 

 of germination of the zygospore of Mucor, and still better 

 in the germination of the oospore of the Peronosporacete. 

 The oospore of Fythium may either grow out to form 

 a complete mycelium, with sporangia and sexual organs, or 

 may develop into a sporangiophore, or, finally, may itself 

 become a sporangium. So far as we know, this last method 

 of germination has become hereditary in Ci/stojms. Simi- 

 larly in the primitive Ascomycetes the whole generation is 

 reduced to a single ascus, and at the inception of this 

 degenerate tVuctificative generation the peculiar nuclear 

 fusion steps in. Commencing with this condition in the 

 primitive Ascomycetes there exist all stages between a 

 unicellular ascogonium producing only one ascus, to a 

 multicellular ascogonium which, with (?) or without fertilisa- 

 tion, gives rise to many asci. AVhether the transverse 

 septation of the ascogonium stepped in before or after the 

 disappearance of any trace of a male organ is a detail ; 

 but the ascogonial thread and its branches are togetlier 

 analogous to the suspensor of flowering plants, and the 

 production of a number of young asci in it is comparable 

 to the polyeni bryony of those Gymnosperms that bear 

 several embryos on one suspensor. Finally, the apparent 

 proihiction on higher Ascomycetes of many asci, quite 

 apart from any ascogonium, may be compared with the 

 adventitious production of embryos from the nucellu.3 of 

 Angiosperms. On the other hand, the production of many 



1 This view has already been supported by Dr. D. H. Scott, in his 

 address to the liritish Association, 1«90. 



