386 BOTANICAL GAZETTE [NOVEMBER 
assumes a tetrahedral form, each angle of which points into one of 
the four lobes of the spore mother-cell. This form persists through 
synapsis and the spirem condition, and only disappears with the for- 
mation of the spindle. 
While the chromosomes are being differentiated, and while there is 
still a trace of linin connecting them, fibers may be seen extending 
over the points of the tetrahedral nucleus as caps and into the nuclear 
cavity (fg. 7). With the appearance of these fibers the nuclear mem- 
brane becomes less distinct, some of the fibers finally occupying the 
position which it formerly held. During this period the incompletely 
differentiated chromosomes lie scattered irregularly throughout the 
interior of the nucleus. 
With the complete disappearance of the nuclear membrane and 
the further growth of the fibers, this four-rayed structure rapidly 
passes over into a bipolar spindle and the chromosomes, eight in 
number, become clearly grouped in a ring to form the nuclear plate 
(fig. 2). I have found no evidence of their quadrupling in number, as 
was sO positively asserted by Farmer. It is difficult to follow the 
development of the bipolar spindle from the four-rayed structure of 
prophase because the figure is small, but there is probably a rearrange- 
ment of the elements through the establishment of a single axis, around 
which the fibers and chromosomes become grouped. 
Now follow two divisions in rapid succession without an intervening 
resting condition. There is no four-poled spindle in Farmer’s sense, 
but well-organized bipolar spindles without centrospheres, and the 
chromosomes are distributed in the usual manner. ig. 3 illustrates: 
the metaphase of the first division and fig. g shows anaphase of the 
same. In the latter case the daughter chromosomes are seen to be 
grouped in a ring at the poles of the spindle. There appears to be 
no resting period. The second division begins immediately, the rings 
of chromosomes altering their positions so that their planes lie at right 
angles. Two distinct spindles are organized, their axes being perpen- 
dicular to each other. ig. 5 presents the conditions at metaphase of 
the second division and fg. 6 illustrates anaphase when the mitoses 
of the spore mother-cell are completed. It should be noted that the 
two spindles of the second mitosis are entirely distinct from each 
other. My preparations show hundreds of examples similar to the 
Stages that I have figured. 
It will be seen that the foregoing account agrees substantially with 
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