1902] BINUCLEATE CELLS IN HYMENOMYCETES 23 
De Bary’s view as to the relationship of the rusts and Ascomy- 
cetes must be given up. 
Further, it is plain, in view of the above facts, that the 
processes of nuclear fusion in asci and basidia are, so far as the 
present evidence goes, entirely unrelated morphologically, and 
that ascus and basidium are not to be brought into any common 
category as oogonia, as is attempted by Dangeard. Neither 
the cells of the ascogenous hyphae nor the vegetative mycelial 
cells of the Ascomycetes are binucleated in any case so far inves- 
tigated, and there is no suggestion of any close morphological 
resemblance between ascus and basidium. The significance of 
the fusion is not entirely clear in either case, but no light is 
thrown on this point by endeavoring to bring together such 
heterogeneous structures. 
It is highly probable that the nuclei of the basidium, as of 
the teleutospore, are of widely separated ancestry. It is clear 
in the case of Pyronema, at least, that the nuclei which fuse in 
the ascus are not sister nuclei. Further than this the resem- 
blance in this respect does not extend. The origin of the asco- 
carp in a sexual process is analogous to nothing which has so 
far been discovered in the Basidiomycetes. It may well be that 
both the origin and the physiological significance of the fusions 
in ascus and basidium are entirely distinct. 
MADISON, WISCONSIN. 
LITERATURE CITED. 
BREFELD, O.: Bot. Untersuchungen iib. Schimmelpilze III. 1877. 
2. DANGEARD: Mém. sur la reprod. sex. des Basidiomycetes. Le Bot. 4: 
IIg. 18 
DANGEARD and SAPPIN-TROUFFY: Une eRe as chez les 
Urédinées. Compt. Rendus 116: 267. . 
. DE Bary: Comp. morph. and biol. of sas bacteria, and mycetozoa. 
Oxford, 1887. 
Harper, R. A.: Sexual reproduction in Pyronema confiuens and the 
morphology of the ascocarp. Annals of Botany 14: pl. 19. fig. 2. 
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HARPER, R. A.: Nuclear phenomena in certain stages in the — 
ment of the smuts. Trans. Wis. Acad. Sci. 12: 475-499. 
