LEVINE: CyTOLOGY OF HYMENOMYCETES 171 
The question as to the possible morphological equivalence of 
the carpophore of the Basidiomycetes and the ascocarp of the 
Ascomycetes is a difficult one. The development of the ascocarp 
is in many cases at least initiated by functional or possibly non- 
functional sex organs. It is possible that in the apogamous 
Ascomycetes which have been reported as lacking an ascogone, the 
ascocarp may arise in the same fashion as does the carpophore 
in the Basidiomycetes. It is to be noted however that binu- 
cleated mycelia are not so far known to occur in these apogamous 
Ascomycetes. 
I am of the opinion that in the Boleti at least none of the cells 
of the hymenium may be properly regarded as paraphyses. They 
are all binucleated when young and are all potentially either 
basidia or cystidia. That certain of these cells serve merely as 
‘“‘space makers”’ is an interpretation which appears to me to be 
without much proof. Certainly there are no paraphyses here 
which can be compared to those in the Ascomycetes. In the latter 
the paraphyses are typically gametophytic while in the Basidio- 
mycetes all the elements of the hymenium are just as certainly 
sporophytic. 
The constancy in the occurrence of a nuclear fusion followed 
by a double nuclear division in the basidium is now generally 
conceded. Uninucleated basidia such as those of Hygrophorus 
conicus reported by Maire (1902) and Fries (19117) are apparently 
rare exceptions. The young basidia of twenty-four species of 
Boleti and three species of Polypores which I have examined are 
all binucleated. The two nuclei fuse in all cases and the resulting 
nucleus divides twice, forming four nuclei. These four nuclei 
migrate to the spores and there divide again. 
It is an obvious conclusion that these two nuclear divisions 
in the basidium involve the reduction of the chromosome number 
but the small size of the nuclei makes it impossible to reach new or 
independent conclusions as to the nature of the reduction process. 
Fries (1911!) and Kniep (1911) hold that the first and second 
divisions in the basidium are respectively heterotypic and homoe- 
otypic. But it cannot be said that their figures give any very 
positive evidence on the large questions here involved. My prep- 
arations show clearly (PL. 6, FIG. 27) that the number of chromo- 
