346 Fault . — The Cytology of 
period of vegetative activity between the initial and the final phases of the 
sexual act. 
Maire (’00-02), Harper (’02), and Nichols (’04) have investigated a 
number of species of Autobasidiomycetes and have found that the cells of 
the lamellae of the Agaricaceae, and of the entire fruiting body and even 
part of the mycelium of some other forms, are binucleate, though so far no 
one has determined where or how this condition arises. Fruitful investiga- 
tion is rendered difficult in most forms because the cells which might be 
expected to contain two nuclei are ordinarily multinucleate and the number 
of nuclei is not at all constant. Maire asserts the belief that where more than 
two occur in such cells the increased number is due to an amitotic multipli- 
cation of an original pair. The nuclear phenomena in the basidium have 
been studied by Wager (’93), Dangeard (’93), Maire (’02), and Fries (’ll), 
and have been found to closely correspond to those in the teleutospore. 
Thus there is reason to believe that the same type of sexuality is expressed 
by the Autobasidiomycetes as by the Rusts. 
The problems presented by the Ascomycetes have appeared at first 
sight less complicated in some respects than in the Basidiomycetes, owing to 
the existence among them of more or less conventional and in some instances 
apparently functional sexual organs, and the failure to recognize conjugate 
nuclei. A closer examination has revealed the fact, however, that a nuclear 
fusion takes place in the ascus just as it does in the basidium, and that the 
sexual organs exhibit a more perplexing multiplicity of forms than in any 
other group of plants. Several botanists have reported, too, that they have 
seen gamete nuclei fusing in the oogonium or its equivalent, and there is 
increasing evidence of the occurrence of characteristic conjugate nuclei. 
Indeed, the ensemble of facts has appeared so difficult of reconciliation that 
so far no view has been advanced that has not called into question the 
actuality of the existence of some one of them. 
Harper (’96, ’05), seconded by Blackman and Fraser (’06), Fraser (’08)> 
and Claussen (’05), has contended that there are two successive nuclear 
fusions within the limits of a single life cycle, one in the female gametan- 
gium, the other in the ascus. They have actually seen both — at least, so 
they have interpreted what they have seen — but, granting the correctness of 
their interpretation, it is pertinent to insist that their claim that both occur in 
the same life cycle is a pure assumption. If their contention be correct, then, 
according to prevailing views regarding chromosomes in conjugating nuclei, 
there must be a quadrupling of the chromosomes with the second fusion, and 
in consequence a compensatory double reduction. Harper (’05) has con- 
sistently accepted this apparently inevitable theoretical deduction, and 
locates the site of the two reductions in the ascus. He considers that the 
double reduction is effected by the three mitoses in the ascus — an alluring 
hypothesis because of the obviousness of one meiosis and the universality of 
