— 122 — 



of the smallest to the largest, but soon the picture changes and the 

 difference becomes distinctly apparent, as shown on fig. Ki. The 

 nuclei of the first type, that is the larger ones, take indubitable 

 share in the further development of the fungus. The figs. 6, 7, 

 show such nuclei lying in the cells of an ascogonium, which has 

 already produced ascogenous hyphae. It was impossible to trace 

 the nuclei of the second type. Probably, they were delayed in their 

 development and having grown in dimensions they at last take the 

 appearance of the other nuclei. 



Passing, л^ithout any definite order, sometimes in groups, some- 

 times in pairs, into profusely branching ascogenous hyphae (fig. 6)^ 

 the large nuclei of the ascogonium evidently quickly divided, though 

 the process of dividing, was not once observed. One may define it 

 by the great augmentation of their number and at the same time 

 their diminution in size. 



If, in the cells of the ascogonium, une could not notice nuclei 

 arranged in pairs, quite the contrary could be observed in the 

 ascogenous hyphae. One can say with certainty that the nuclei in 

 these latter are disposed in pairs, that is easy to observe. At the 

 end of the ascogenous hyphae the nuclei passed into the hooks 

 (fig. 9). The further development of the ascus followed its ordinary 

 course and was not specially studied. 



The investigations thus permit us to put the P. fimiseda quite 

 definitely into the group of ascomycetes, Avhich has a normal develo- 

 ped ascogonium, gi^ing rise to ascogenous hyphae. and in which,, 

 at the same time, one can notice the complete absence of antheri- 

 dial cells. But it is to be seen that there is one essential question, 

 that of cytological character, which remains unsolved; the fact is 

 that in the cells of the ascogonium, at a certain stage of develop- 

 ment, one can notice the formation of large and small nuclei. This 

 question has gi-eat importance, and is very interesting, for it is in 

 direct relation with the question of the so called .,double fusion"- 

 of the nuclei of the ascomycetes, to which in recent years so much 

 attention has been given. It is quite natural, on seeing these nuclei, 

 to suppose, that large nuclei are produced by the fusion of two- 

 small ones and that here has taken place the first „Harpers fusion" 

 in the female cell, after which the ascogenous hyphae are produ- 

 ced. Cutting (Ascophanus), Dale (Aspergillus.), AVelsford (Ascobolus) 



