286 BOTANICAL GAZETTE [OCTOBER 
(fig. 26). The fusion nucleus grows rather rapidly, and as this 
continues the chromatin soon comes to be arranged in a definite, 
fine spireme (fig. 27). When this condition has been reached, the 
spireme does not usually show any free ends, and it can frequently 
be traced as a continuous thread for considerable distances. It 
is impossible, however, to follow it through some of the tangles. 
Frequently threads run to the nuclear membrane or nucleolus, after 
which it is not possible to trace them further. This suggests that 
the spireme is not continuous throughout its entire length, but 
this conclusion must be considered doubtful, as it is difficult to 
follow a spireme along the nuclear membrane, which is usually 
irregularly thickened, or to distinguish it from the nucleolus when 
it is in contact with the latter. While the nucleus is still far from 
its final size, the spireme shows the approach of synizesis by begin- 
ning to collect in a tangle either around or to one side of the nucleo- 
lus (fig. 27). This usually continues until all of the spireme is 
arranged in a dense tangle in which little detail can be seen (fig. 
29). No evidence of a fusion of spiremes during this stage was 
observed. An examination of figs. 27 and 28 will show that the 
spireme is not double as it goes into synizesis. The spireme was 
occasionally seen contracted into a mass about as dense as the 
nucleolus. This extreme condition may have been due to fixa- 
tion, but the regular occurrence of synizesis at this stage, and in 
material in which the fixation seemed to be perfect, certainly seems 
to indicate that synizesis is, as Mortrrer (29) thinks, a stage in 
development, and not an artifact due to fixation, as is claimed 
by SCHAFFNER (32). This view is supported by the fact that the 
spireme is quite different in appearance before and after synizesis. 
ynizesis probably lasts for a considerable time, as the nucleus 
and ascus grow considerably during this period. 
At the end of synizesis the spireme, which is now much thicker 
than before, loosens up and becomes spread through the nucleus 
(figs. 30 and 31). The continuity of the spireme throughout its 
length at this stage is, just as before synizesis, doubtful. After 
the spireme has become spread through the nucleus, it splits longi- 
tudinally (fig. 32). This splitting appears to extend through almost 
if not quite the entire length of the spireme. The two halves, 
