142 LEVINE: CyTtToLOGy oF HYMENOMYCETES 
The basidium is a spore mother cell and not an egg and the 
nuclear fusion in it is associated with the phenomena of chromo- 
some reduction. Maire describes and figures a synapsis stage 
in the prophases of the first division and gives good figures of 
centrosomes, polar asters, etc., in a number of forms. In Sclero- 
derma vulgare he found a deeply staining granule on the wall of 
the resting nucleus, which he believes to be a centrosome. As to 
the number of chromosomes, Maire is plainly in error. His 
figures showing two chromosomes are due to poor fixations and 
the true chromosomes are undoubtedly shown in his protochromo- 
somes. He first observed the appearance of cytoplasmic threads 
connecting the nuclei and the sterigmata at the four-nucleated 
stage of the basidia. He believes that the nuclei move into the 
sterigmata by the contraction of the threads and thus finally reach 
the spore. Maire observed this process of nuclear migration in 
several agarics, a boletus, and a puff ball. 
Maire also discovered the interesting and as yet unexplained 
abnormalities of the basidia of Hygrophorus conicus and H. 
ceraceus. Their subhymenial cells and young basidia are uninu- 
cleated. The nucleus in the basidium, which is bisterigmatic, 
divides, forming two nuclei which migrate into the spores. Oc- 
casionally one of the nuclei in the basidium divides before entering 
the spore, in this case the two nuclei migrate to one spore while 
the undivided nucleus goes to the other spore where it divides. 
In Clavaria rugosa and Cantharellus cinereus he observed as many 
as three divisions of the secondary nucleus. In the latter species 
a variable number of spores are formed, from one to five, irrespec- 
tive of the number of nuclei. 
The observations of Wager, Juel, and Maire, as to the ap- 
pearance of the spindles, astral rays, centrosomes, etc., were con- 
firmed in the main by Ruhland (1901). He describes the nuclear 
phenomena in a number of Basidiomycetes (see table, p. 164). He 
denies that four spores are ever formed on the basidium of Hyd- 
nangium carneum, although the phenomena leading up to the 
four-nucleated stage are quite regular. He claims that either one 
or two spores may be formed. When two spores are formed two 
nuclei pass into each. In case only one spore is formed all four 
nuclei migrate into it. 
