Wager . — The Sexuality of the Fungi. 593 
another, coming as they do from one cell, to allow its being 
regarded as sexual. But, as has already been pointed out, 
this objection does not hold if we regard the fusion of 
adjacent cells in Spirogyra and Basidobolus as sexual. For 
in these cases the two nuclei may be as closely related as are 
those of the basidium or the ascus. And the objection would 
certainly not hold in the case of the Uredineae if Sappin- 
Trouffy’s observations are correct, for the nuclei are far 
enough removed in relationship, although they are found 
in the same cell. If with Sachs we could regard each 
nucleus with its protoplasm as representing a separate unity 
(Energid), it seems to me that, in the Uredineae at any rate, 
and possibly in the Ustilagineae and Basidiomycetes, we 
might consider these nuclear fusions as indicating a sexuality 
nearly equivalent to that in Basidiobolus. 
Or we might regard these nuclei with Hartog 1 as the centres 
of potential gametes, in which case the nuclear fusions would 
be of the nature of those parthenogenetic fusions which take 
place in the eggs of Artemia , in Saprolegnia (if Hartog’s obser- 
vations are correct), in the azygospores of Sporodinia (accord- 
ing to Leger 2 ), and in Derbesia , where the zoospores have 
nuclei constituted by the fusion of several vegetative nuclei, 
a process which, according to Hartog 3 , replaces the formation 
and union of gametes. But it seems to me that the evidence 
before us is not sufficient to enable us to come to any definite 
conclusion one way or the other, and a most serious objection 
to Dangeard’s view that it is a true sexual process is found 
in Harper’s observations on Sphaerotheca and other simple 
forms of the Ascomycetes. These observations show that we 
have in these cases two distinct nuclear fusions. The first 
appears to be morphologically a true sexual fusion of two 
nuclei from different cells, resulting in the production of an 
ascogonium ; the second, a fusion of two or more nuclei in 
the ascus which occurs at a definite stage in the life-history, 
and results in the formation of ascospores. What is the 
meaning of this second nuclear fusion ? 
1 Hartog, loc. cit. 2 Leger, loc. cit. 
3 Hartog, loc. cit. 
