1906] BRIEFER ARTICLES . 351 
The young basidium first appears as a club-shaped branch from the 
sub-hymenial layer. It is more densely filled with protoplasm than in 
older stages and contains two nuclei. The structure of these nuclei can 
be made out very easily. Each nucleus has a rather large deeply staining 
nucleolus, a network in which the chromatin granules are imbedded, 
and a distinct nuclear membrane. 
As the basidium increases in size the nuclei fuse together into one 
large nucleus. At first the two nuclei lie side by side with their mem- 
branes in contact and without apparent change. Then the membranes 
disappear at the point of contact. The nucleoli remain distinct for a 
short time, but finally fuse so that the large secondary nucleus produced 
by the fusion contains but a single nucleolus. The manner of the fusion 
of the threads bearing the chromatin could not be made out. After this 
fusion, the nucleus increases in size and comes to occupy a position near 
the upper expanded end of the basidium (jigs. 6 and 7). 
At this stage the structure of the nucleus can best be determined. 
It is so large that it fills more than two-thirds the diameter of the basidium. 
The nuclear membrane is very distinct, so that the nucleus stands out 
very clearly from the contents of the basidium, which at this stage have 
become vacuolate. The nucleolus is large and stains deeply, taking a 
reddish color with the triple stain. The nuclear network consists of one 
or more coiled threads in which are imbedded the chromatin granules, 
which stain blue or purple. Between the coils of the thread are the 
colorless spaces which are filled by the nuclear sap in the living cell. 
The nuclear division takes place in the manner described by WAGER 
(5) for A. muscaria. The chromosomes are produced from the thread 
bearing the chromatin granules. The number of chromosomes is small, 
but I have been unable to determine the exact number. The chromo- 
somes are small and stain deeply. The spindle consists of a small number 
of fibers, but they do not show the structures of fibers very clearly because 
they are crowded closely together. The spindle is arranged transversely 
near the apex of the basidium and is long and narrow with a small deeply 
staining body at each pole. Such spindles as the one shown in fig. 8 
are found frequently in the preparations. After the chromosomes move 
to the poles there are a few persisting spindle fibers which connect them. 
The daughter nuclei are now formed and usually occupy a position near 
the apex of the basidium (fig. rz). Each daughter nucleus has the same 
form and structure as the parent nucleus. 
The most important question now is whether these two nuclei divide 
again to produce four nuclei, as is the case in plants with four spores on a 
